Low Torque question

[dfurlano]

I purchased the g540 and got it installed and working on my X2. I am using a keling 48v power supply. On the x-y I have I Pac Sci Powermax II P22nrxd-ldf-ns-00 motors rated at 1.25A and 65V.

When I power up the system the x-y axis motors have very low torque. I can with one finger move the or stall the motors. After reading everything it looks like the only option is to increase the size of the resistor from 1.2k to something larger?

I previously had a xylotex controller that I was using for about two years and the torque on the motors was much, much higher.

Any insight would be appreciated.

Thanks

Dan

[TOTALLYRC]

Originally Posted by dfurlano I purchased the g540 and got it installed and working on my X2. I am using a keling 48v power supply. On the x-y I have I Pac Sci Powermax II P22nrxd-ldf-ns-00 motors rated at 1.25A and 65V. When I power up the system the x-y axis motors have very low torque. I can with one finger move the or stall the motors. After reading everything it looks like the only option is to increase the size of the resistor from 1.2k to something larger? I previously had a xylotex controller that I was using for about two years and the torque on the motors was much, much higher. Any insight would be appreciated. Thanks Dan

Page 49 of this document has all the details

http://www.pacsci.com/support/docume...er/stepsel.pdf

The 1.25 amps is in series. if the motors are wired in parallel, you would need to set the current resitor for 2.5 amps

Of course this all assumes they are 8 wire motors.

[dfurlano]

I have the 4 wire motors.

I am easily confused but in the wiring diagram table it states that the 4 wire is in parallel so I would need the 2.4k resistor?

[TOTALLYRC]

Originally Posted by dfurlano I have the 4 wire motors. I am easily confused but in the wiring diagram table it states that the 4 wire is in parallel so I would need the 2.4k resistor?

If it is in fact a 4 wire motor and you are sure it is parallel, then yes you would need the 2.4 ohm resistor to set the current. You are current running it a half power which will make a big difference.

I would do 1 motor first and the run some basic g-code that runs the motor around for 5 minutes. All the while checking the motor temps by hand. If it gets too hot to comfortably keep your hand on the motor is seeing too many amps. Warm is ok and an indication that you are at or near optimum power. You can't just let it sit to see if it gets hot ,as the drive has an idle current reduction and they really won't overheat at idle.

Lets say you do the x first. something like this basic g code.
g01 f5 x5
x0
x5
x0 and so on if your table is bigger than 5 inches use a bigger number.

Mike

[Mariss Freimanis]

Did you measure your resistor with an Ohmmeter?

Mariss

[dfurlano]

Mariss,

Thanks for your reply. I did check the resistors with an ohm meter and verified the color coating. I am confident that I need to use a 2.4k resistor for these motors. I did send PacSci an email to confirm.

I do have another question but I will wait till I replace the resistors and confirm the issue before I ask.

Thanks

Dan

[Mariss Freimanis]

Also try plugging in the motor cable to the G540 and measure the resistance then (power off of course). Verify you still have 1.2K. If you don't, double check your solder connections on the off chance they may be shorting to pins 2,3 or 4 on the DB9 connector. Those pins are GND and will short-out the current set resistor, giving you near zero torque.

As a double check, turn power on, set your meter to DC Volts and measure the voltage across the resistor. A 1.2K resistor will read 1.2VDC across it.

Mariss

[dfurlano]

I just checked the resistor both unplugged and plugged in and got the same reading ~1.27k ohms.

[dfurlano]

I changed the resistors and it seems to be working fine.

But I do have another question.

In the tuning window of Mach3 with the Xylotex controller the "steps per" was set to 8000 with the G540 I had to change it to 800, I used a indicator to figure this out. That does not make sense to me since I believe Xylotex microstep was set to 1/8 and the G540 I believe is fixed at 1/10. But I could not find any information either way.

Just does not seem correct to me.

Dan

[TOTALLYRC]

Originally Posted by dfurlano I changed the resistors and it seems to be working fine. But I do have another question. In the tuning window of Mach3 with the Xylotex controller the "steps per" was set to 8000 with the G540 I had to change it to 800, I used a indicator to figure this out. That does not make sense to me since I believe Xylotex microstep was set to 1/8 and the G540 I believe is fixed at 1/10. But I could not find any information either way. Just does not seem correct to me. Dan

Just a guess to see if I am even remotely close. And I am sure Mariss or Marcus will chime in with the correct answer. I think it has to do with the way the drive morphs from micro to full step on the fly. The software is just outputing steps and then the drive goes from micro to full step. somhow this has to be compensated for. I will take a wild guess and say that the drive is setup to be full step to the software and then does some wild math while it is running to be were it is supposed to be. Kind of like a step multiplier on the other drives.
Remember this is a guess!!!!

[ger21]

Wrong guess. :-) I replied to the OP on a different forum. The G540 should be 10,000 steps per inch. I have no idea how it's working at 800.

[TOTALLYRC]

Originally Posted by ger21 Wrong guess. :-) I replied to the OP on a different forum. The G540 should be 10,000 steps per inch. I have no idea how it's working at 800.

That is why I made sure we knew I was guessing.