LONG POST - Apologies
(somewhat of a cross-post here...)
Using Mach 3, Version R3.043.022
Using xylotex XS-3525/8S-4
Using cnc4pc C11 Rev 7.2 board
Using Harbor Freight Mini-Mill (44991) with stock DC motor
Over the holidays I got a hand-held tachometer and decided to check the spindle speed of my Mini-mill (HF-44991) against what it was showing in Mach3. Now mind you I had control in the ability to increase or decrease the rpm's before all this started.
I noticed that the speed was off by a several hundred rpm and decided to tune it. So here we go. I tried the automatic spindle calibration within Mach3 R3.043.022, but decided to cancel before I got to far since it seemed to be taking way too long. I then began just typing in the speed and checking against the tach and created a table of corresponding spindle rpms vs tach rpms.
I've restarted Mach3, I've saved settings, etc., but I can't seem to get the changes to take place.
Not sure how the AutoCal works since I don't have any feedback to system regarding RPM. I did note that when selecting AutoCal the software does in fact cause the speed to increase gradually, but I always stop before it ends due to the latter reason.
On the motor tuning of the spindle, I have:
Steps per: 1000
Velocity: 1500
Accel: 161.25
Step Pulse: 4
Dir Pulse: 4
Odd thing is, I can't change the Velocity. I can type in new numbers but when I click somewhere else on the dialog, the number reverts to 1500. (found out later it's because of the acceleration number, change that and you can change the velocity; posting here for someone else's benefit).
On the Ports and Pins, Spindle Tab:
Motor Control is set to Use Spindle Motor Output and Step/Dir. If I disable it, I can't get the spindle to turn at all.
"ModBus Spindle - Use Step/Dir as well" is disabled
"Special Functions - Use Spindle Feedback in Sync Mode" is disabled
Since I didn't know where to go about making changes, I started with adjusting the pulley, but later found this is only a scaling for what's displayed in Mach.(posting here for someone else's benefit).
THE ISSUE: I can't control the speed at all. I can see an increase in voltage from the C11 output as I increase the speed in Mach3, but now the motor only comes on at around 5V and runs max speed. Even increasing the voltage doesn't make an increase in actual motor rpm. In fact it starts the spindle motor to grunting like the brushes are about to come out.
I reinstalled Mach3 and created a whole new config file from scratch, but it didn't resolve the issue, unless I still have my spindle motor tuning incorrect.
I tested the rpm's with two other DC motors (tread mill type) and the issue is the same.
I tested with another speed controller with both DC motors and again the issue is the same.
All three motors were acting just like my mill motor in that they both made a grunting type sound due to the inconsistent voltage that is being applied. I had always thought it was the crappy brushes of the original mill motor, but now I know that it's related to the constant on/off voltage or something.
I say something because both speed controllers are indicating 95v to 100v coming out of them going to the connected spindle motor. Once I get the output voltage of the C11 up to around 5V (by adjusting in Mach3, not the pot), the motor will come on. I still can't get any increase in rpm by increasing the spindle speed in Mach3. What's really odd is that when I continue to increase the speed in Mach3, that's when the slight decrease in RPM starts to occur and consequently the grunting starts.
I believe I have adequately proved to myself that it isn't my motors and it isn't my speed controllers.
Again, the only thing I changed on the C11 was rotating the potentiometer. I don't see any discoloration anywhere on the C11 board, chips or otherwise. I pushed on all the chips to check for tightness to be sure there weren’t any issues with them being loose.
I now have the spindle tuning set to 1000 steps/per, the velocity maxed out (~6000) and the acceleration set to 6.25, and the spindle motor still runs wide open regardless of the spindle motor tuning settings.
I've contacted Arturo and he's looked at the xml I sent him, but I said the xml looks fine. Hood, over in the Mach3 forum said the xml looked fine as well.
That's why I'm posting here since I don't know whether it's Mach or the C11 board.
Any help would be immensely appreciated! I would gladly call anyone willing to talk to me. Send me a PM with your phone number and I'd make the call.
Thanks in advance,
Vogavt