Copyright (C) 1986-2008 by Daniel H. Hudgins, All Rights Reserved.

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This Web site is dedicated to the thousands of "users" of my programs, those who have helped test my programs over the last 22 or so years, and especially those who shared their experiences with me.

You must read this notice: This is a licensed Web site (HTML document and associated files). You must read and agree to be legally bound in contract by the Terms of Use and conditions given in the End User License Agreement ("EULA"), Legal Notices, Instructions, Warnings, Disclaimers, and all other text in "SECTION: 0" of "This Web Site" (HTML document and associated files) before reading or using any of the information, software programs, and or files, contained in, linked to, and or associated with, "This Web Site" (HTML document and associated files). Any use or "Beta Testing" of "This Web Site" constitutes your acknowledgment of your full agreement with the current End User License Agreement ("EULA") and your decision to have this current license supersede all prior and contemporaneous agreements and understandings. Information and files in "This Web Site" (HTML document and associated files) have been placed here so that long time users of "The Author's" programs DANCAD3D.COM (tm) , DANCAM.EXE (tm) , or DANPLOT.EXE (tm) could help proofread the text of the documentation files or screens displayed, and also help test data files, example files, and or any software programs that might be made available from time to time, to aid "The Author" in finding mistakes, bugs, and other errors, omissions, defects, mistakes, and faults. Everything in "This Web Site" (HTML document and associated files) is "Beta Test", "Beta Code", Experimental, Preliminary, requires proofreading, or is being evaluated for possible revision, and is NOT warranted to be free of defect. To help "The Author" report any bugs, foul-ups, defects, or mistakes that you find, see "SECTION: 8" for instructions. "This Web Site" (HTML document and associated files) and all other files and programs by Daniel H. Hudgins are made available "AS IS" without warranty of any kind express, expressed, or implied. All offers and specifications are subject to change or discontinuation without notice of any kind. Please read "SECTION: 8" of "This Web Site" (HTML document and associated files) before trying to contact "The Author."

This documentation section has text mostly about DANCAM.EXE (tm) and DANPLOT.EXE (tm), my CAM programs, and might be looked to for information on some of the CAM program commands. See also the other documentation files, and pages in this Web site, for additional information. The disclaimer and most of the other legal text has been moved to SECTION: 0 , you must read the disclaimer, End User License Agreement (EULA), and other legal text, before you read any of the other documentation or use any part of this HTML document or associated files and programs. Be sure to read all the Warnings in SECTION: 3.2.10.0 , and the other documentation, before running, installing, testing, or using any of my programs, and especially before using DANCAM.EXE (tm) and DANPLOT.EXE (tm).

The text in this section was derived from the CAMPLOT.DOC file that was in the original v2.6 distribution, and has been updated somewhat so that some of the changes made in v2.7 are reflected. It may take me some time to get back to work some more on this section, but you can help proof-read what is here now. Some adjustment may be required for versions prior or subsequent to v2.72 since there are variations between versions and the various revisions of versions.

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Documents may be available to download from time to time, you can check SECTION: 9 to see what the current situation with regard to downloadable files is. The names of these documentation files may change, and they may be edited, combined, or eliminated in the future, without notice.

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Use the "Edit, Find in page Ctrl+F" or "Edit, Find (in this page)... Ctrl+F" command in your browser to search for keywords within the documentation text in this HTML page. You will need to search over again in the other pages in this HTML document for the same keyword since your browser may not search for a keyword beyond the current page that is loaded.

If you do not want to install all of the programs and files from the distribution DANCAD3D.ZIP (tm) file onto the computer that will run a machine, you can copy just the essential CAM files, and make the needed sub-directories, manually.

For DANCAM.EXE (tm) v2.72 you need to copy:

EXAMPLE: C:\DC27>FORMAT A: /S /U
         C:\DC27>C:\DC27\COPY DANCAM.EXE A:
         C:\DC27>C:\DC27\COPY DANCAM.OVR A:
         C:\DC27>C:\DC27\COPY DANCAD3D.808 A:
         C:\DC27>C:\DC27\COPY DANCAD3D.814 A:
         C:\DC27>MD A:\XFER
         C:\DC27>MD A:\ASCII
         C:\DC27>MD A:\CYCLES

For DANPLOT.EXE (tm) v2.72 you need to copy:

EXAMPLE: C:\DC27>FORMAT A: /S /U
         C:\DC27>C:\DC27\COPY DANPLOT.EXE A:
         C:\DC27>C:\DC27\COPY DANPLOT.OVR A:
         C:\DC27>C:\DC27\COPY DANCAD3D.808 A:
         C:\DC27>C:\DC27\COPY DANCAD3D.814 A:
         C:\DC27>MD A:\XFER
         C:\DC27>MD A:\ASCII
         C:\DC27>MD A:\CYCLES

Be sure that you create any sub-directories you may need to use while the programs are running, particularly the \XFER\ sub-directory used by the network commands. You might make two 1.44MB floppy disks with "DOS 95" on them so that you can boot your computer without using the harddisk. It is better to run the CAM programs with a computer that has the EMS driver loaded so that the overlay file will not spin the floppy disk each time part of the overlay is to be accessed, to save space on the floppy disk you can sometimes include a file path in the AUTOEXEC.BAT or CONFIG.SYS files that looks for the EMS driver, mouse driver, CD-ROM driver, Joy-Stick port enable driver, and other such files on your harddisk.

Do not move the floppy disks that you configure the CAM programs on from one computer to another computer, since the programs adjust their timing to the computer they are configured for. Mark the floppy disk so as to indicate which of your computer's that floppy disk is specifically configured for so that you do not accidentally use that floppy disk in the wrong computer.

The program files for v2.7 of my CAM programs take more disk space than previous versions, and are broken into two parts i.e. the DANCAM.EXE (tm) file or DANPLOT.EXE (tm) and their DANCAM.OVR or DANPLOT.OVR overlay file. The default DANCAD3D.808 and DANCAD3D.814 screen font files also need to be available for use by the programs.

Normally the *.OVR is kept in the same directory as the *.EXE file so that the *.EXE part of the program can find the overlay file. When the CAM programs are run on a computer that does not have a harddisk and there is not enough room for the program and overlay files on the same floppy disk, it is possible to relocate the *.OVR overlay file to another floppy disk, e.g. you could put the *.EXE file on drive A: and the *.OVR file on drive B:.

Since the programs cannot be run until the program can find the overlay, the location of the overlay cannot be in the configuration file. Therefore a special additional configuration file can be created called DANCAM.OVP or DANPLOT.OVP corresponding to the CAM program you are using. This *.OVP file only contains one line of text that has the full path to where the overlay file is kept. The program appends the name of the overlay file, so do not include the name of the overlay file, only its path.

You can use the DOS COPY command to make this *.OVP file, or use any editor that can save a DOS *.TXT type file.

EXAMPLE: A:\>COPY CON DANCAM.OVP
         B:\OVERLAY\
         ^Z

                 1 file(s) copied

         A:\>

After you type in the B:\OVERLAY\ you should press [Return] and then press the [Ctrl] key and hold it down, then press the [Z] key, and let both keys up, then press [Return] again. To view the path that you currently have in the *.OVP file you can also use the COPY command,

EXAMPLE: A:\>COPY DANCAM.OVP CON
         B:\OVERLAY\
                 1 file(s) copied
         A:\>

Notice that the overlay path needs to end in a backslash character since the overlay file name is directly appended to the overlay path found in the *.OVP file.

Generally you will only have to use the *.OVP file if your computer is limited to two 360KB floppy disks. If your computer has just one 1.44MB floppy disk and no harddisk you can make a separate boot floppy for DANCAM.EXE (tm) and DANPLOT.EXE (tm). If your tool path files are too large to fit in the free space on the floppy disk, you can try to use the built in computer network to execute the tool path directly off of a computer running another copy of the CAM programs that is acting as a file server. When the CAM programs are operated on the network some temporary files are created for compressed files, and for the disk directories, therefore there needs to be some disk space free for those features to be used. How much disk space needs to be free for the CAM programs to use the network depends on the size of the files being transferred, the transfer mode being used, and the number of entries in a file directory being requested. You should try to keep at least 500KB free at all times on the disk the *.EXE part of the CAM programs is running in, but you might be able to get by with 50KB free if you do not use the compressed transfer modes, and do not request long file directories. If you have network problems check the Serial port IO delay value, and the free disk space, on all the computers on the network even if the error messages seem to indicate some other data problem.

When you execute tool path files in the CAM programs you are given the choice of executing the tool path file from a tool path file stored on one of the computer's disks, or you can select the tool path source as one of the serial ports that is connected by cable to another computer running a copy of the CAM programs and is acting as a tool path file server. When a file is executed from a file stored on the network file server the data in the tool path file is received one byte at a time, so files larger than any of the disk drives on the shop computer operating the machine might still be executed, this would be important when the shop computer does not have a harddisk, or the harddisk is of low capacity.

In order for DANCAM.EXE (tm) and DANPLOT.EXE (tm) to make parts that come out to the proper size you need to properly answer some questions in the configuration menus of DANCAM.EXE (tm) and DANPLOT.EXE (tm). Additionally you need to test the motors to determine the maximum reliable speed, set up the feed rate to line color table, set up the auxiliary relays and home switch's options, and use the automatic feed rate and timing self calibration command to adjust the programs to your computer's speed and timing.

DANCAM.EXE (tm) and DANPLOT.EXE (tm) send messages to the motor translator driver modules in the form of what are called "steps." The motor shaft rotation is divided into fractions, usually 1.8 degrees per step, or 200 steps per 360 degrees (360/200=1.8). Sometimes stepper motors are run in "half step" mode where the step is divided in half, e.g. 400 per revolution of the motor shaft. Micro stepping divides the stepper motor step into smaller parts, but does not usually offer higher actual positional accuracy under fluctuating loads since the motor shaft of a stepper motor will typically exhibit 0.9 degrees of positional error when driven under full load from clockwise, and then counter-clockwise rotation.

For servo motors the optical shaft encoder defines the minimum rotational interval or "step." Servo motor electronics can sometimes "multiply" the number of encoder lines by 1x, 2x, or 4x, so with a 500 line encoder you might get a choice of 500, 1000, or 2000 steps per revolution. For a given step rate the number of steps per revolution determines the motor shaft RPM, at 4000 steps per second a servo motor with a 500 line encoder would turn 480 RPM at encoder 1x, 240 RPM at encoder 2x, and 120 RPM at encoder 4x.

In version 2.7 the default unit name inches is displayed in the configuration menus in DANCAM.EXE (tm) and DANPLOT.EXE (tm). You can use the configuration menu to change the units names any units can be used so long as all of the configuration set up is done using the same units of measurement. My CAD programs just save numbers in the tool path file, the conversion of those number's values to distances moved is controlled by various values you enter into the CAM programs configuration menus, and the actual construction of your automated machine, e.g. one unit the the CAD program drawing editor can become one inch, one cm, one mm, one foot, one micron, or one some other type of unit in your machine.

The CAM programs have an overall scaling factor in their configuration menu. This overall scaling factor lets you adjust the part size, or convert tool path files drawn in metric units to inch size for a machine set up for inches, or the other way around. If you get confused about the scaling factors, set the global scale in DANCAD3D (tm) at 240 and configure DANCAM.EXE (tm) and DANPLOT.EXE (tm) to move in steps per one inch, and set the DANCAM.EXE (tm) or DANPLOT.EXE (tm) overall scaling factor to 1, then one unit in DANCAD3D (tm)'s drawing editor will move the tool one inch. The default configuration is for one unit in the CAD tool path drawing to come out as a one inch motion in the automated machine, so long as you enter the right number of steps per inch for your automated machine's construction.

Since the motor shaft has a finite number of stopping positions, or steps, the driven load will also have finite positions it can stop at. When working out the ratio of the timing belt pulleys for the motor and lead screw you should figure that one motor step should move the work-piece relative to the tool by one half the smallest amount necessary. If you are machining to a tolerance of 0.001 of an inch, you could use a 10 pitch lead screw with a 1:1 coupling to a 200 step per revolution stepper motor, since this arrangement will give you 0.0005 inches of movement per motor step, i.e.:

 200 steps per revolution
 --------------------------  =  2000 steps/inch  =  0.0005 inches/step
 0.1 inch per revolution

The reason you want twice the required resolution is that stepper motors will "over-shoot" about one half step while running, and can also lag behind about half a step under load.

Successfully installing DANCAM.EXE (tm) or DANPLOT.EXE (tm) requires having the motors installed to give the coarsest resolution that will be acceptable. Excessively fine resolution will limit the maximum speed the tool can move, this is because the maximum steps per second that the motor can operate at is constant. Reducing the resolution will increase the maximum speed the tool can travel. In our example we can calculate the maximum tool feed speed in inches per minute from the motor RPM, since with 1:1 drive the tool will move 0.1 inch per revolution, and 120 RPM might be a reliable maximum speed for the motor shaft.

120 revolutions per minute
--------------------------  =  12 inches per minute
 10 revolutions per inch

Feed rates for other resolutions can be worked out for the motor shaft speed of 120 RPM and 1:1 shaft coupling:

----------------------------------------------------------------------
|    FEED RATE WITH FULL STEP STEPPER MOTOR RUNNING 120 RPM (1:1)    |
----------------------------------------------------------------------
|   LEAD SCREW | FEED/REV | STEPS/INCH | INCH/STEP | INCHES/MINUTE   |
----------------------------------------------------------------------
|     2.5 tpi  |   0.4"   |     500    |   .002    |      48         |
|     5.0 tpi  |   0.2"   |    1000    |   .001    |      24         |
|    10.0 tpi  |   0.1"   |    2000    |   .0005   |      12         |
|    20.0 tpi  |   0.05"  |    4000    |   .00025  |       6         |
----------------------------------------------------------------------

If the motor is half stepped and the motor is coupled through a 1:2 set of timing belt pulleys the feed rate can be doubled and the resolution held the same, i.e. one turn of the motor shaft for two turns of the lead screw. Unfortunately when stepper motors are half stepped they have about half of the torque as when the motors are full stepped, because to half step, the motor alternates between two coils on and one coil on, normally in full step mode you have two coils on all the time. You also further divide the torque in half when you "gear up" the pulleys 1:2. So going from full step 1:1 coupling, to half step 1:2 pulleys divides the torque by 4. Also when running the motor at full speed you only get about 0.25 the rated stopped holding torque, therefore you will need a motor rated for (holding torque of) 8 to 16 times the torque required to move the tool if you want to half step the motors and gear up the lead screw.

----------------------------------------------------------------------
|    FEED RATE WITH HALF STEP STEPPER MOTOR RUNNING 120 RPM (1:2)    |
----------------------------------------------------------------------
|   LEAD SCREW | FEED/REV | STEPS/INCH | INCH/STEP | INCHES/MINUTE   |
----------------------------------------------------------------------
|     2.5 tpi  |   0.8"   |     500    |   .002    |      96         |
|     5.0 tpi  |   0.4"   |    1000    |   .001    |      48         |
|    10.0 tpi  |   0.2"   |    2000    |   .0005   |      24         |
|    20.0 tpi  |   0.1"   |    4000    |   .00025  |      12         |
----------------------------------------------------------------------

Since the torque of stepper motors falls off the faster the motor turns you may only be able to get reliable operation at speeds slower than 60 RPM. In general doubling the voltage used to drive a stepper motor will increase the top speed by at most 50%, i.e. if a motor works well at 60 RPM at 24 volts you can probably get it up to 90 RPM by increasing the voltage to 48 volts. The top voltage for operation of stepper motors is about five to ten times the rated voltage, but if you operate stepper motors at higher than their rated holding voltage you also need to limit the current to the motor's rated current to avoid burning out the motor. In the simplest current limiting scheme a series power resistor is used to limit the current flowing through the motor winding when the motor is not turning, to the motor's rated current, this resistor is helpful because the motor is an inductive load and the resistor will allow the voltage to rise briefly at the beginning of each motor step before the voltage drops across the motor winding back to the static position holding level, thereby making the motor turn faster.

When building a plotter you can drive the pen holder by using a timing belt driven directly by a pulley. Small motors can generally run up to about 240 RPM in half step mode to give 1600 (half) steps per second. This type of belt or cable drive can be useful in applications where speed is more important than resolution. If servo motors are used in place of stepper motors with belt drive, speeds of 120 inches per second, or more, might be able to be achieved. The table below shows the results of the resolution and feed rate for using a half stepped stepper motor operating at 240 RPM.

----------------------------------------------------------------------
| PULLEY DIAMETER | FEED/REV | STEPS/INCH | INCH/STEP | INCHES/SECOND|
----------------------------------------------------------------------
|     0.25"       |  0.785"  |   509.55   |  0.00196" |   3.14159"   |
|     0.50"       |  1.570"  |   254.65   |  0.00392" |   6.28318"   |
|     0.75"       |  2.356"  |   169.76   |  0.00589" |   9.42477"   |
|     1.00"       |  3.141"  |   127.32   |  0.00785" |  12.56636"   |
----------------------------------------------------------------------

When selecting stepper motors to drive your equipment you should use motors that have a rated holding torque of at least four times the torque that will be required under load and at full speed. Also use the motor testing utilities built into DANCAM.EXE (tm) and DANPLOT.EXE (tm) to do the start and stop test to make sure that the spacing of the pulses sent to the motor translator module are far enough apart (a larger pulse width factor, p.w.f., will space the step pulses wider apart) for the motor to keep up with the step pulses coming from the computer. If the step pulses are to fast the motor will not come back to the point it was at at the beginning of the motor test, indicating unreliable operation, and the need to use a larger p.w.f. value. The in version v2.6 and prior the ramping should be set to 0 when testing stepper motors.

The start and stop motor test utility purposefully sends step pulses to the motor that are irregularly spaced in order to determine the fastest starting, or pull-in, speed that the motor can accept without losing steps, that is, that the motor is no longer having the motor's shaft at the commanded position because the rotor could not keep up with the rapid switching of the motor's coils. Your goal in testing the motors is not to set the p.w.f. values to the smallest value that worked once, but to set the p.w.f. values to values that work every time and under all conditions of stress, so that when you operate your automated machine from a tool path file and try to make something you have some hope that the motors will be able to keep up with the step pulses and move the tool to the commanded positions. You may have to set the motors to run quite slowly to get satisfactory reliability.

If you cannot get the motors to run slowly enough by changing the p.w.f. value for an axis, you can use the p.w.f. increaser option in the configuration menus in v2.7 to increase the pulse spacing and make a given p.w.f. value operate the motors at a slower speed. In extreme cases of excessive computer speed your motors may not turn at all, until you make the p.w.f. value 10000 to 20000, and the p.w.f. increaser 100 to 200 or more.

To make the motors go as fast as they can on slow computers, you can set the p.w.f. to 0, and the p.w.f. increaser to 1. If that is not fast enough you can use the pulse rate multiplier in the programs configuration menu with servo motors, or perhaps some types of micro stepper drivers, to send more than one pulse for each step, so if you use a pulse rate multiplier value of 10 the motor would turn about 10 times faster, provided the motor could keep up with the computer's sending of the rapid pulses.

The original speed ramping feature operated below the pull-in p.w.f. speed and was mostly intended for linear motions for use with servo motors so that the step pulses speeded up and slowed down gradually to allow for the time it takes the servo motor controller to adjust the motor drive current. In v2.7 a new "overdrive ramping" feature was added to speed up and push stepper motors above their safe pull-in speed for rapid point to point movements. Running the stepper motors above their pull-in speed may not be reliable in many applications, but for some applications like drilling PC boards using a computer running DOS, you might be able to use the overdrive ramping and rapid motion type to speed up the throughput by one and a half or more depending on how much extra voltage the stepper motors can take. To get stepper motors much above their normal pull-in speed you need to use a higher than normal amount of supply voltage, and make adjustments to limit the motor current. Do not use the overdrive ramping with servo motors, or for applications where the stepper motors operate heavy loads or need to be more reliable. The overdrive ramping needs to be tested by using the Jog command, and the motion type for the feed rate color needs to be selected so that rapid movement type mode is used. The reason that you need to use Jog to test the rapid type movements, is that in order to ramp up to full speed you may have to command your machine to move from one end of its range to the other end, and the motor testing utilities do not know anything about the size of your machine or where the motion limits are, therefore you use the Jog command to put the carriage at one end of the range of motion and Jog to the other end of the machine at rapid feed rate using the rapid motion type, see if the motor stalled, make adjustments to the overdrive p.w.f. and try again until you find an overdrive p.w.f. that seems to work well for rapid movements over the full travel of your machine. You need to use the configuration menu to select the rapid motion type for any given line color value, the rapid motion type should not be used for operations requiring linear motion type. The motion type for the various line colors is selected in the feed rate table.

I would like to warn you that stepper motor manufacture's published speed vs. torque curves may sometimes indicate speeds that may not be generally applicable to use with DANCAM.EXE (tm) or DANPLOT.EXE (tm). As a rule of thumb you might expect these values as your maximum top speeds for reliable error free operation under working load, with the higher RPM number being obtained by using the maximum voltage the motors can take. When the voltage for the stepper motor is more than six times the rated voltage stepper motors may become unstable in the middle of the motors speed range, so you are limited in how much the motors can be boosted. Therefore you may not even be able to get much more than half the values in the table below in your machine.

----------------------------------------------------------------------
|       MOTOR HOLDING TORQUE     |     MAXIMUM MOTOR SHAFT SPEED     |
----------------------------------------------------------------------
|          20 -   40 oz-in       |           240 - 300 RPM           |
|          40 -  150 oz-in       |           120 - 240 RPM           |
|         150 -  400 oz-in       |            90 - 120 RPM           |
|         400 - 1500 oz-in       |            30 -  90 RPM           |
----------------------------------------------------------------------

One problem you might find with the stepper motor manufacture's specifications is that they might measure the torque using a technique that allows the motor to be losing steps, i.e. the rotor is slipping, while the motor is running. They are not lying in as much as the motor actually produces that torque stated at the specified RPM, but they might fail to point out to you that this is probably useless information if you are interested in accurate open loop operation of the motor. For the operation to be accurate the rotor must never be more than one half of a full step (or half of a half step) from the position dictated by the number of step pulses sent to the driver module. Also the motor must be able to work at all speeds between the maximum and stopped without "resonating" and losing steps. The stepper motor must also be able to consistently move the working load of your automated machine, and not just a light fractional load in a laboratory test.

Also a manufacture might rate the holding torque at a current that is the maximum the motor can take without burning up or demagnetizing the rotor, rather than the current that would give the best and most accurate performance over the full range of speeds. I am mentioning these things to think about because I do not want you to look at what might be some optimistic specifications some manufacture might someday publish and spend a lot of money on expensive hardware when you might get nearly the same "real world" performance while using my programs by using much less expensive parts. If possible test any hardware yourself to confirm its utility before you order and pay for it.

To configure DANPLOT.EXE (tm) and DANCAM.EXE (tm) to produce the proper number of steps per inch of travel run DANCAM.EXE (tm) or DANPLOT.EXE (tm) from DOS and select mode #4, i.e. change configuration file, from the CAM program main menu. The various options in the configuration menus let you enter values that adjust the CAM program to fit your automated machine. Before exiting the configuration menu you should use the automatic feed rate and timing self calibration command to adjust the program to the speed of your computer.

Typically stepper motors can only step 300 to 1000 full steps per second, or 600 to 2000 half steps per second, so a motor step delay of about 0.5 ms to 3 ms, or 500 microseconds to 3000 microseconds, is needed to keep the stepper motors following the step pulses. The minimum single step delay for each motor axis is controlled by a value called the "pulse width factor" which is also referred to by the abbreviation p.w.f. in the programs and documentation. Each axis has its own p.w.f so the motors can run as fast as possible, i.e. at their allowable pull-in speed, when the maximum feed rate is requested. If you find that one of your motors is losing steps, i.e. an axis gets off position, try increasing the p.w.f. value for that motor axis by 25%, and re-test to see if that axis then works better.

The overdrive ramping p.w.f. value will be equal to or less than the linear movement p.w.f. that is set to the motors safe pull-in speed. The value for the overdrive p.w.f. will generally range from the pull-in p.w.f. to about half of the pull-in p.w.f. For example, if you run the start and stop test on the X axis and find that a pull-in p.w.f. of 1500 works well, you might set the overdrive p.w.f. for the X axis to 1200 and then use the Jog command to test the X axis motor to see if it will stall when moving the X axis in rapid feed motion type over the full length of the machine's travel. If the motor stalls, increase the overdrive p.w.f, if the motor runs well decrease the overdrive p.w.f. until the motor stalls, then increase the overdrive p.w.f. to a value that is reliable. When using servo motors, or in cases where you would not want the stepper motors to operate above their pull-in speed, you should set the overdrive p.w.f. to the same value as the regular linear pull-in p.w.f. for each of the axis.

Problems other than the p.w.f. being too small can cause the motor's to be off position, such as electronic interference of various types. You will need to check for problems other than the configuration values to make sure your automated machine is ready to use for "Beta Testing" in the making of parts.

When you install DANCAM.EXE (tm) and DANPLOT.EXE (tm) using their main menu option configuration menu, CAM program main menu option #4, be sure to work through the sub-menu options in order #1, #2, (in sub-menu of #2 use options to adjust p.w.f. test #1, start and stop test #2, RPM test #4, and timing self calibration #5, etcetera, for each axis) and then do configuration root menu options #3, #4, and #5, and so on.

When you work through the configuration menus keep in mind the number of steps the motor shaft makes per revolution, i.e. the number of step pulses required to make the motor shaft rotate once around. If you run a motor in half step mode, you will need to multiply the number of motor steps by two. If you use a micro stepping driver enter the number of micro-steps you have your driver set to. The motor steps per revolution multiplied by the pitch of the lead screw gives you the number of steps per linear unit, e.g. steps per inch. For servo motors you may get a fractional number for the steps per revolution if a rate multiplier is used. If a belt or cable drive is used you may get an odd value for the steps per linear unit.

EXAMPLE: 200 steps/revolution * 5 tpi lead screw = 1000 steps per inch

         400 half steps/revolution * 10 tpi lead screw = 4000 steps per inch

         2000 micro steps/revolution * 4 tpi ball screw = 8000 steps per inch

Note that in the micro step example the motor shaft can still push or pull a half step or more off the commanded position under load, so the actual positional resolution is probably more like 1/(400 * 4 tpi) = 1/1600 = +/- 0.000625 inch under fill load, rather than 1/8000 or 0.000125 inch you might think you would get looking at the number of step pulses required to move one inch, unless the stepper has a closed loop encoder wired to work as a servo loop, which is not typical since many micro steppers operate open loop with no feed back. Whatever the actual mechanical resolution is, in the configuration menu you will be entering the number of steps per linear unit, e.g. inch, which is just the step pulse count required by the motor driver module, and not a measurement of the movement of the tool. You may be able to make up for some of the lost motion on direction reversals with micro steppers by adjusting the amount of backlash compensation you enter into the configuration set up, backlash is a measurement of the tool movement, or lack thereof.

For servo motors the number of steps per revolution can be derived from the encoder counts per revolution and any hardware pulse rate multiplier or divider used. Some servo motor controllers increase resolution by multiplying the lines in the optical encoder by 2 or 4, such that a 500 line encoder will really give 1000, or 2000 counts (steps) per revolution.

The rate multiplier in configuration root menu option #1 lets you have more than one pulse sent for each motor step signal. This is useful to speed up some kinds of micro stepper or servo motor controller driver modules that have excess resolution. If you have a micro stepper that has a setting of 20000 steps per revolution you can set the CAM program step pulse rate multiplier to 10 or 20 to reduce the micro stepper driver module resolution to a speeder 2000 or 1000 steps per revolution. When driving regular stepper motors full step the rate multiplier should almost always be set to 1 pulse per step.

If you have a machine where you have servo motors on your x and y axis, and a full step stepper motor on your z axis, I think there is a "trick" you can use if you need to use the rate multiplier for the servo motors. Since the rate multiplier sends pulses that are generally too fast for a full or half step stepper motor to keep up with, you can set the rate multiplier to multiples of the full steps, or half steps, plus or minus one. This might work because the stepper motor cannot "see" the rapid change in the motor coil voltage, and the stepper motor moves to the coil last state. If you set the rate multiplier to 5 the full step motor will move one step forward, if you set the rate multiplier to 3 the full step motor will move one step backwards. In a half step motor a value of 9 would move one step forward, and 7 one step backwards. Values for full step motors would them be 5, 9, 13, 17 for forward, and 3, 7, 11, 15 for reverse motion, and so on, i.e. (3 cycles * 4 counts) + 1 = 13, or (2 cycles * 4 counts) - 1 = 7. Some values for half step motors might be 9, 17, 25, 33, for forward, and 7, 15, 23, 31 for reverse motion, and so on, i.e. ((3 cycles * 8 counts) + 1 = 25, or (2 cycles * 8 counts) - 1 = 15. Other values would make the stepper motor stall and or probably not work properly. If you pick a value that makes reverse or backward motion, you might need to change the configuration set-up or your machine's components to compensate.

The CAM program's motor tests are mostly for finding values that adjust the speeds that stepper motors in your machine can be operated at and not get off of the commanded position. Many factors effect the ability of the stepper motors to operate properly, so you cannot calculate these speed controlling values, they can only be determined by experiment. Any changes you make to your machine, changes to the computer, changes in the electronics or line voltage, temperature, machine adjustments, dirt or oil, and other influences will require you to re-test your configuration values and make adjustments to compensate for the changes.

Since servo motors "always" catch up to the commanded position the motor tests do not help very much in setting them up. For servo motors you can use the Jog command and, if you are able to, measure the position error value from servo driver to see how rapidly you may have the speed ramping operate. When you plot a drawing using a machine with servo motors if you see that corners and sharp angles are getting rounded off, or the lettering looks like squiggles, you probably have the motors running with the speed ramping change too rapid. The start and stop test can test the quality of your servo motor controller by having the program repeat the test over and over again, the marks you make on the motor shaft and the motor body should line up after the test finishes, just be sure that you bolt the motor down to something or the motor may shake violently and cause problems! If the servo motor does not come back to its starting position after the start and stop test you probably have some electronic interference with the encoder signals, your controller's encoder input filter needs to be adjusted, or the controller may not be working properly or may be of inferior design. My motor start and stop test is included to cause the motors to get out of position if everything is not operating as it should, i.e. to torture test. The point of doing a torture test is to see if any errors can be detected, since servo motors should never lose steps and be off position when they come to a stop.

In the motor test sub-menu, i.e. option #2 in the configuration root menu, use the sub-menu option #1 to find the smallest pull-in p.w.f. that makes the motor run smoothly under load, then use option #2, the start and stop test, (#2 of #2 of #4 from the CAM programs main menu) to check that the motor is not missing any steps (make the p.w.f. value larger if the motor is missing steps and test again), and use the RPM test, in v2.7 option #4, to test the maximum pull-in RPM speed. When the pull-in p.w.f. has been configured for each axis press [Esc] to go back to the installation sub-menu and answer the other questions. The regular ramping should be set to 0 for testing stepper motors. The overdrive ramping needs to be tested by using the Jog command. Note that the motors do not need to be running, i.e. powered, for the RPM test to work if you are testing "open loop" motors, i.e. stepper motors.

Be careful when using the RPM test, since the motor being tested will run for one minute at full speed, and so may run your tool past the end of your machine and break something. If you are testing open loop motors, such as stepper motors, it is better to have the motor power off when doing the RPM test. When testing servo motors in their on state you will need to disconnect the motor from your machine and attach a "dummy" load to the servo motor so that you do not run your machine off one end of its travel. Also if servo motors are on, you may overrun their motor driver module's position counters, and cause the motor to stop, reverse, or do strange things. If you adjust your servo motor's p.w.f. using the Jog-menus you can probably run the R.P.M. test with the servo motor disconnected, and so avoid the problems mentioned. If you are using the pause input on the parallel port to "sense" when your servo motors are running not as fast as the step pulses from the computer, the servo motor would need to be on in order to slow down the computer properly. See also the other comments about the RPM test below.

When you perform the start and stop test, menu selection #2 of #2 of #4, you need to mark the motor shaft and also mark a fixed point near the motor shaft lined up with the mark on the motor shaft before you use the start and stop test. After the start and stop test has finished the two marks should line up again. If the two marks do not line up you lost some steps. You can adjust the pull- in p.w.f. to a larger value, then use the Jog command to line the two marks up again, and then try the start and stop motor test again. Several things can cause lost steps are listed below where: P. stands for problem, S. stands for solution:

1. P. The p.w.f. for the axis under test is to small making lost steps.
   S. Increase the p.w.f. until the error is removed.

2. P. The motor is over loaded even when run slowly.
   S. Use a larger motor, timing belt reduction, or reduce the load.

3. P. Your load has to much inertia and or not enough friction.
   S. Drill lightening holes, add some friction, or a viscous damper.

4. P. The motor is not getting the proper voltage and current.
   S. Adjust the module current setting or the series power resistor.

5. P. Electrical noise is upsetting the module logic circuits.
   S. Add a low pass filter or opto-isolator on the input of the translator module.

6. P. Some mechanical part is lose or slipping.
   S. Avoid parts that can slip like cable drives, and use thread lock.

The RPM test in the motor configuration sub-menu will work with stepper motors being switched off. The only time the motor needs to be on is if you have a servo motor hooked up in "closed loop" with the servo driver error hold line feeding back to the pause input on the parallel port. A note of warning about the RPM test, the motor will run for one minute which may drive your machine to the end of its travel and beyond and possibly break something, so switch the motor off before running the RPM test if you are going to have an out of range problem. Another problem that can occur with the RPM test is that since servo motors go so fast you may overflow the servo motor controller's position register making the motor suddenly reverse direction at full torque! So think about how far your motor will move in one minute and see if you will have a problem. If your limit switches are wired up the motor should stop when the limit switch opens. If a servo motor is at full speed it may overshoot the limit switch a little, so it is a good idea to use limit switches that can take some movement beyond the trigger point. See also the other comments about the RPM test above.

The questions in option #3 in the installation sub-menu configuration root menu should be used to install the scaling factors, e.g. steps per inch, before you enter the feed rate values with option #4. In version 2.7 of DANPLOT.EXE (tm) and DANCAM.EXE (tm) the feed rate is controlled by an internal delay imposed between motor steps, this internal delay is calculated from the time and distance value entered in the feed rate table and the computer's speed measurements made during the operation of the self calibration command. Since the pull-in p.w.f. sets each motors maximum pull-in speed, the feed rate is imposed to slow the motors down from the maximum speed set by the pull-in p.w.f.

In v2.7 the feed rate can vary from the maximum speed determined by the p.w.f. values, p.w.f. increaser, and other factors, down to very slow speeds depending on how slow you want the feed rate to be. To get different feed rates while the tool moves, enter the feed rates you want for the various tool path line colors into the feed rate table, then make the tool path drawing with DANCAD3D (tm) so that the line segments have the color attribute number that corresponds to the color number for the feed rate setup in the CAM program's feed rate table. In order for the feed rates selected to operate you need to use the automatic self calibration command for the feed rates and timing, option #5 in the motor testing sub-menu, to adjust the CAM program to your computer's speed.

The line color attribute is set while drawing in DANCAD3D (tm) by pressing the [L] key of the keyboard while in the drawing sub-menu of the drawing editor or by using the mouse to click on the [L]ine style option of the [L]ines sub-menu from the drawing editor root menu. Various feed rate values can be assigned to the line color numbers in the CAM programs feed rate table. Set all of the feed rates to a large value if you want the tool to move as fast as possible for all motion.

When using the teach mode in the CAM programs, to create a tool path file, you can select the line color that will be saved for each movement, and in that way control the feed rate that will be selected when the saved tool path file is executed.

Since the relays, dwell, and programed pause for machine operator, are also controlled by the tool path line colors keep in mind what the feed rate will be when these other options are triggered when the tool path is executed and contains a line segment in that tool path of a particular line color.

Version 2.7 has 127 feed rates in its feed rate table. Use the configuration menu command to alter the feed rates assigned to particular line colors. The line colors displayed on the screen for the various line color numbers is controlled by the color palette, which you can change buy using the Palette command in the CAD program's drawing editor's Set-up sub-menu. The CAM programs can read a palette file saved from the CAD programs in order to have the screen colors match the line color numbers in both programs.

In versions prior or subsequent to v2.7 there may be differences to how the p.w.f. and feed rates are set-up and configured, please see the program menus in the version you have for applicable information.

There is another configuration menu option that can let you assign which line color attribute numbers, in the tool path file, will turn on or off the auxiliary control relays. Line segments used to control the auxiliary relays can have starting and ending points at the same location, i.e. dots of zero line length, if you do not want the motors to move, but want the relays to change state. In DANCAD3D (tm) you can draw a zero length line, i.e. dot, in the drawing editor draw menu by pressing the [Del] key and then pressing the [Ins] without moving the drawing cursor between the two keypresses.

In the CAD programs you can make the auxiliary relay control dots in your tool path that you draw stand out on the drawing editor screen if you turn on the WYSIWYG feature, and make the line width of the dots larger than 1, perhaps 10 to 50 or so. To change the line with for lines to draw use the Line style command in the Lines edit sub-menu of the drawing editor. Using the square equal line end caps attribute will give a square dot, and using the round equal line end caps attribute will give a round dot. If dots of different colors are going to overlap or be in the same position, make the first dot the largest width and the last dot the smallest width, so that the last one does not cover up all of the others when the screen redraws.

Once an auxiliary relay is turned on by the CAM programs it remains on until a line segment is encountered that has the special color to turn it off. This allows the four relays to be individually turned on an off at different times.

When a tool path file is being executed, before the motors start to turn to follow the line segment, the line color is checked against the installed options to see if one of the auxiliary relays needs to be turned on or off. The feed rate installed for the line color of the currently executed line segment will set the speed of the motors. The auxiliary relay to line color configuration will turn on or off the relays as configured. The auxiliary relay options let you assign a delay after the relay turns on so that the device being turned on is active before the motors start to turn. Likewise when a line color signals a relay to turn off, a delay can be set to make sure that the device is fully off before, the motors continue to turn. When a line color is read that activates a relay the relay state will be stable until another line segment is encountered that is configured to effect the status of the relays, or the tool path ends. For example, if you have line color #3 set to turn on auxiliary relay "A" and line color #8 to turn off auxiliary relay "A" then when the file is executed and a line segment with color #3 is read the relay will toggle on and stay on while other color line segments are read so long as the other line segments are not color #8.

The auxiliary relay on, off, or no change state is selected for various line colors in the "Aux" columns of the feed rate table in the CAM programs. The delay values for the four relay outputs are selected in the auxiliary relay setup command. Note that the program will only ask you for the relay A and B delay values, unless you enable the C and D relay outputs, since the C and D relay outputs are sometimes used to pull-up the switch input pins on the parallel port. In DANPLOT.EXE (tm) the relay A and B outputs are sometimes used for the C axis step and direction signals, so you should enter neutral values for the A and B relay outputs if you use the C axis.

It might be possible to add one or more extra axis to your machine by using the auxiliary relay outputs to switch the step signals from the X, Y, or Z axis to another motor driver module. If, for example, you switch the X axis to four other motors you would get 7 axis total, if you switch all three axis to four other sets of three motors you would get 15 axis total, and so on. You might arrange some TTL logic AND and NOT gates to send the step signals to one motor when an auxiliary relay output on the parallel port is logic hi (1), and another when the relay output on the parallel port is logic low (0). The additional motors might be used to rotate a part that is being milled for cutting of gear teeth and other sorts of "indexed" manipulations where only 3 of the many axis need to be moving at any given moment. The line colors in the tool path would be drawn so as to select which of the many axis would be moving at any given time.

Another feature the line segment colors can control is an automatic pause for machine operator. Putting an automatic pause in your tool path might allow you to adjust your automated machine before cutting actually begins, or to have you fill something that needs refilling, like the paint pot for making oil paintings, and such. The pause for machine operator is selected for various line colors in the "delays" column of the feed rate table in the CAM programs.

The dwell that can be triggered by specific line colors in the tool path file is like the automatic pause, but rather than waiting for the machine operator automatically continues after the assigned delay period. The dwell time is setup in the "delays" column of the feed rate table in the CAM programs.

Option #5 of the installation sub-menu asks about the home switches. Both DANPLOT.EXE (tm) and DANCAM.EXE (tm) let you install home switches on your equipment so that you can have the tool automatically home up to the starting point, i.e. home position on your machine, before each tool path file is read. The ability to home up automatically can be a great time saver since you do not need to manually jog the motors to their starting position. If you turn the motor power off and then back on stepper motors may "jump" to a position several steps away from the motor's position before the power was turned off, so without the home switches installed you would need to manually check the home position every time you turn the power on.

Both DANCAM.EXE (tm) and DANPLOT.EXE (tm) allow you to select if you want to use the option to have the tool automatically homed up to the home switches at the start of each tool path file. If you wish to start with the tool in some starting position other than where the machine homes up to the home switches, you can turn off the automatic home up feature, manually select the home up to switches from the menu, then use the Jog position command to move the tool to the special starting point measuring from the home switch starting position, and then execute the tool path from that special starting point.

The position of the home point relative to DANCAD3D (tm)'s workspace center, i.e. X = 0, Y = 0, Z = 0, needs to be entered into the configuration menu so that the proper displacement (offset) will be added to the line segments in the tool path when the tool path file is executed. For example if you have a plotter that is 24" by 36" you would install the home point as 12 and 18 so that the tool home point would be at the corner of the drawing area, and the center of the drawing would be X = 0, Y = 0, and Z = 0. You can install the home point as X = 0, Y = 0, and Z = 0, as well if you wanted to, but you would have to draw in DANCAD3D (tm) with the elements off center in the workspace, or at least offset your tool path drawing to be off center before you save the tool path file. If you wish to use the perspective display to view the drawing lines for a 3D tool path file in the Preview command in the CAD programs, it is best to have the tool path centered in the drawing work-space, and have the home position in the automated machine located at the half the automated machine's working range away from the center point.

Another reason for having the home position at the extreme margin of the plotting area is so the mechanical backlash compensation will work properly. Since the backlash compensation takes up all the "slack" on the first move in the tool path file, you cannot have the tool to return from "behind" the starting, i.e. home, position. Installing the home switches at the end of the automated machine's travel is what the programs expect. The home position values in the DANCAM.EXE (tm)'s and DANPLOT.EXE (tm)'s configuration menu for the most part are there to just let you shift the relationship between the points in DANCAD3D (tm)'s workspace and the range of motion of the tool in your automated machine. You need to decide if you will locate your work- pieces in the center of your machines working range, or locate your work-pieces always at one corner of your machine's working range, so that you can create your tool paths and know where, i.e which way, the tool will move to for the first cut.

If you do not use the home switches to home your tool before you start your tool path, you will need to use the Jog command to position the tool at the right starting point, making sure that you take up the backlash the right way around for the move to the first point in your tool path. The CAM programs normally return to the home point by moving away from the work- piece.

When you draw your tool path files your roughing cut lines should be back from the finish cut line by about twice the amount of backlash for each axis. If you do not make the roughing cuts back from the finish cut line, the tool may drag the work- piece around and cut past the finish cut line. The weight of the work-piece and the friction in the machine ways is generally enough to keep the work-piece from being pushed and pulled out of the correct position if you take only very small cuts from the rough cut line up to the final finish cut line, if not increase the friction on the machine's ways.

DANPLOT.EXE (tm) has some additional special configurations. The "C" axis lets you mount a fourth motor with its shaft parallel to and centered on the Z axis such that a knife, saw, gauge, paint brush, or broach will automatically rotate to point the cutting edge into the motion of travel. The tolerance value on the C axis lets the tool stay down while cutting out quasi curves. Generally the C axis tolerance value before tool lift should be set to between 10 and 20 degrees. There is an option to display the angle for the C axis tool. Normally the display of the C axis angle would be turned off to get the best speed, however you can use the display of the angle for testing, or for manually rotating the tool by placing a protractor on the tools axis and matching the reading of the protractor to the displayed value. The angle matching would need to be done while the machine is paused, and in a way that is safe, perhaps in conjunction with the manual Z axis mode.

DANPLOT.EXE (tm) also has a manual up and down mode. The manual up and down mode option lets you manually activate the Z axis for use in automating a drill press with just two motors, i.e. one motor for X axis and one motor for Y axis. In the manual up and down mode the work-piece is positioned by the CAM program using the values from a tool path file and then the computer is made to pause while you drill the hole, then you press a key on the keyboard and the work-piece will move to the next position, you drill the next hole, and so on. The words UP and DOWN appear on the computer screen while the computer is paused to tell you where the tool should be, i.e. up and clear of the work-piece or down and cutting the work-piece. You can also use the Z axis direction pin on the parallel port to turn on a lamp or buzzer to aid you in keeping track of what you should be doing with the up and down motion of the tool. For drilling the manual up and down mode might be useful in reducing drill breakage caused by the drill clogging during automated operation. Precautions need to be taken to prevent the work-piece from moving while the tool is in the down position, to this end switches can be arranged and wired to TTL chips so as to block the parallel port step signals from reaching the motor driver modules, and pause the computer, until the tool is safely locked in the up position.

Other tasks where the "tool" is to be operated manually, such as spot welding, or where the cutting operation needs to be adjusted during operation by the machine operator (i.e. yourself), such as grinding, might be assisted by having the computer position the work-piece, and then the actual operation at that location on the work-piece would be carried out by the machine operator. The machine for such operations would need to have safety shields to protect the machine operator, and perhaps remote controls for operation of the tool and a video system for the operator to see the remote operation of the tool. Measures to prevent the work-piece from moving at the wrong time would also need to be incorporated in the machine design.

The manual up and down mode could be used for other tasks, such as having the computer position a canvas using a tool path file made using the BMP to ASCII oil painting command, the point to paint could be indicated by a diode laser beam, you would then dab on the paint with a small brush at the point marked by the diode laser beam, and then let the computer move the canvas to the next point to paint in that same color, and so on. Precautions to prevent the laser beam from hurting someone's eyes would need to be taken.

Using the light pointer idea could be extended to having the tool path drawn to indicate the location of parts to insert into certain places on the work-piece. In this way someone could insert parts arranged in order by having the computer point out where the parts should go by putting a spot of light onto the part location. The work-piece could be stationary, and the light beam could be deflected by mirrors on the motor shafts, or by use of an optical galvanometer. A foot switch might be arranged to advance the light to the next point by wiring it across the keyboards [Space- Bar] key.