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Author Topic: Pulse frequency in M3 is low. Driver test okay. Ideas?  (Read 4074 times)

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Pulse frequency in M3 is low. Driver test okay. Ideas?
« on: December 22, 2011, 08:11:09 PM »
Hi all,

I'm just trying to spin my first stepper. Im running a laptop, T43p, WinXP, I reverted AIPC to Standard PC, ran drivertest and came out as excellent. I checked my parallel port cable and had to change its port address (0x3bc not the standard 378) but am still getting errors. The pulse frequency reads somewhere between 1-150 hz, not 25khz, although every once in a while it will show it operating at 25khz for one frame but then revert to <200hz. No pinouts change when I try to jog.

Using KL4030s, C10 board and 425oz in parallel mode, DIPs set accordingly. Wiring is checked and good. Motors do receive power but will not turn.

Any ideas?

Offline ger21

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Re: Pulse frequency in M3 is low. Driver test okay. Ideas?
« Reply #1 on: December 22, 2011, 08:23:59 PM »
A lot of laptops just won't run Mach3 properly. You may have one. You need to disable every power saving feature there is, preferably in the BIOS if possible.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Pulse frequency in M3 is low. Driver test okay. Ideas?
« Reply #2 on: December 23, 2011, 12:55:29 AM »
Hey Gerry, thanks for the quick reply.

Alright so I changed over to a desktop but am still having issues. Desktop is 1.7ghz, 1gb ram, XP.

Right now I have two steppers in parallel config driven by KL4030s (1/8th step, 2.7A) to a C10 BOB (jumpered for pins 2-9 as output, COM as +5V). Drivertest shows that the computer is capable through 100khz,no problems there. When loading M3 up the pulse frequency is 24998 plus or minus 1hz--again no problems. However, there is still no movement from the motors when trying to jog or run a simple program.

Both steppers are receiving power, however on inspection it looks like the B coils of both motors are receiving 1.7V, A coils are at 0.0V. Is this normal? When I try jogging back and forth with either stepper and look at the Dir pins there is no appreciable change in voltage.

Is there anything I'm overlooking?
« Last Edit: December 23, 2011, 12:57:27 AM by KOFT »

Offline ger21

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Re: Pulse frequency in M3 is low. Driver test okay. Ideas?
« Reply #3 on: December 23, 2011, 08:15:47 AM »
Either the port address is wrong, or the port and pin assignments are wrong. If the motors are locked up, then the drives are working correctly.
Checking the dir pin is the right thing to do, as it will tell you when Mach3 is working correctly. If you post your .xml, we can take a look at your settings.

Quote
Drivertest shows that the computer is capable through 100khz,no problems there

I don't put much stock in what the drivertest tells you in regards to what your PC is capable. All that really matters with the driver test is that you get a flat line with no spikes.
« Last Edit: December 23, 2011, 08:18:18 AM by ger21 »
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Pulse frequency in M3 is low. Driver test okay. Ideas?
« Reply #4 on: December 23, 2011, 01:12:56 PM »
Thanks again for the quick reply!

I just checked the port address on the computer, it is reading 0378 - 037F on port 1. I left the port address in Mach3 as the default (0x378). Driver test was indeed smooth with very little noise. I've attached the xml from the setup I'm (trying) to use, let me know if there is anything else I can provide.

I did try another parallel cable a "straight through" connector, and actually it did change things a bit. The first cable I tried using will power the LED on the C10 even if +5v is not applied to it. Looking at the Mach3 diagnostics I see that the first 7 pins are lit up. When I switched to the new DB25 only the first four pins then something like the 10th pin lit up, corresponding to my E-stop. I had to reset the E-stop pin from active low to disengage.

I tested the new cable for continuity and all the pins do in fact go straight through. I'm assuming I should be using this one, correct?

Offline ger21

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Re: Pulse frequency in M3 is low. Driver test okay. Ideas?
« Reply #5 on: December 23, 2011, 01:29:23 PM »
Do the motors spin with the new cable? Can you check the direction pin at the parallel port?
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Pulse frequency in M3 is low. Driver test okay. Ideas?
« Reply #6 on: December 23, 2011, 01:55:58 PM »
Motors still not spinning, but checking the direction pins at the drivers themselves show that they are changing from 0 to 5V depending on increment/decrement. Is there a good layout of which pins on the parallel correspond to which functions?

Although if the dir pins are changing when jogging shouldn't the motors be turning?

Step pins on jogging change from 5V to slightly over or slightly under 5V depending on direction. B coils have a differential of -0.8V (constant while jogging), A coils have 1.4V (constant).