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« Last post by protman16 on January 05, 2026, 05:00:05 PM »
Hello all,
Let me start with I have been a user of Mach3 for a very long time, probably more than 20 years. During the time I have been a user of Mach3 I have been able to test a few different control configurations from parallel port to most recently DMC-40x0 controllers. Of the few control configurations that I have tested over the years I think the DMC-40x0 controllers are very good at providing smooth, accurate, and repeatable motion, but there are some inconsistencies when compared to other controllers that I have used in the past.
On one of the machines that I use, I had the unfortunate idea to update firmware on a motion controller sometime ago in order match the firmware level in another machine that I have. I say unfortunate because the firmware update ultimately bricked the controller which left me looking for a replacement solution. After doing some research (but probably not enough due diligence), I settled on the DMC-40x0 series units due to the used market availability. Mark this is a mistake because there is almost no support from Galil for units obtained by a third party. There is however great documentation available from Galil and other sources that can allow used DMC-40x0 controllers be useful with Mach3, and possibly Mach4 but I have not tested that yet.
The inconsistencies between the DMC-40x0 controllers and other controllers or more specifically, the controller it has replaced, so far are only a few.
1) Jogging – the Mach3 plugin for the DMC-40x0 only allows jogging one axis at a time where as in the past I was able to jog multiple axis’ with the previous controller and all the way back to the PP era. Monitoring the debug file for jog command I noticed that only one JG is issued at a time while the controller can receive many JG commands as long as a BG command is issued after the JG command. I don’t know why only one JG is issued per jog in the Mach3 plugin, but does the Mach4 plugin allows for multiple axis jogging?
2) MPG steps/unit factor – The machines I use have somewhat higher resolution drives in that one unit of travel, in this case inches, requires 80,000 steps for any linear axis. Most MPG’s use 100ppr encoders or 4 steps per detent. And have x1, x10, and x100 selections in order to allow for coarse to fine positioning capability. The previous controller was able to manage the MPG steps per detent well, even though the motion was a little rough when at x100 steps per detent. Since the machine has a resolution of 1/80,000 and even though the physical axis movement at that resolution is barely noticeable, the plugin and DMC-40x0 limits axis gearing to 125:1. This means the most distance that an axis can move at the 80k steps/inch with a 100ppr MPG (400 pulses) for one detent and a 125:1 ratio is 0.00625”. For coarse positioning, this is ok, but it would be nice to maintain the scaling factor indicated on the MPG steps per detent selector without having to resort to customizing the DMC-40x0 for high resolution gearing, or increasing the MPG ppr, or reducing the steps per unit of an axis’. Is there any way to maintain the x1, x10, x100 steps per detent for higher resolution systems through commands for the existing Mach3 plugin or is the Mach4 plugin suited better to handle MPG gearing for higher resolution systems?
3) MPG jog past softlimits – The previous controller would not MPG jogging beyond softlimits once the machine was homed. Currently the Mach3 plugin with DMC-40x0 will allow the MPG to move an axis beyond softlimits at any time. For this machine it’s a little concerning because the home switch is also the limit switch and it does not disable the axis when triggered. I would guess there could be some axis softlimits programmed into the DMC-40x0 when homed but I have yet to look into this. Does the Mach4 plugin softlimits function take into account when jogging from an MPG?
4) Spindle control and tapping – This machine uses a 0-10vdc speed source for a VFD controlled spindle. Relays are used for forward and reverse run functionality. The spindle is belt driven from the motor and has an encoder coupled to the spindle shaft via timing belt. In the past the RPM DRO would display the actual RPM of the spindle at all times, and the machine was able to do tapping. The Galil Mach3 plugin allows for 0-10vdc speed control, and encoder feedback. After some scripting work to m3, m4, m5 macros, and adding some Notifiy Plugins commands, I was able to get the spindle to run in both directions without too much issue. Initially the spindle would max out RPM’s after a second m3 or m4 was issued because the spindle is considered an axis and actual position did not match command on the second start. To manage the spindle speed on subsequent starts, I issue an ST, MO, and DP commands before each start. Overall, this seems to work well for basic speed control and is similar to how the previous controller operated the spindle.
I don’t know how tapping works with DMC-40x0 controller in the Mach3 plugin. To do tapping in the previous controller there was a script that would gear the spindle encoder to the axis that moved the tool to the work piece, or in this case Z axis, so that any motion on the spindle encoder would drive the Z axis at the preset thread pitch. It also controlled the depth too but it was more of guess than anything because you had to tune the decel rate for the given spindle/tap/material combination. I would not trust it to blind holes! Can anyone provide info for what is required to tap with the Mach3 plugin?
For tapping with the Mach4 plugin there is a “Spindle has encoder” checkbox with counts/rev and accel revs/sec fields which is the same as the Mach3 plugin. And there is also info that mentions the spindle must accept +-10v signal should you want to do tapping. There is no mention of +-signal in the Mach3 plugin, but I do know the axis JG command does go negative when in reverse.
How does the Mach4 plugin function for tapping?
Is a servo required? Or can you use a bipolar converter with a 0-10v VFD and encoder?
Will either version plugin drive a step and direction controlled VFD?
5) Spindle orient – Currently I have yet to test spindle orient but I can explain how it was done previously.
The spindle on this machine uses a detent to orient it to a fixed position. There is no option to orient to a specific angle. It works by sending a jog and run forward signal to the spindle while a pneumatic cam roller is actuated. Once the cam roller reaches the detent, an input triggers the run and jog commands to turn off and then after about 500ms the pneumatic cam retracts. At this point the spindle is free to move.
The orient function on this machine is really used to align the spindle for a tool change.
I assume the same functionality can happen with either version plugin regardless of the control method since its essentially done with I/O. What other conditions should be considered than resetting the spindle axis encoder position after orient?
So far that’s all I have noticed to be inconsistent with the previous controller. I apologize for the long post and if some of the answers to the above have been covered before.
Thanks to the Mach community for your input,
protman16
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