Thread: Can't get motor spinning w/Mach3 & g540

I thought maybe it was the parallel port or a PC problem, so I took another PC I had lying around, formated the HD and did a fresh install of Win XP. Put Mach3 on and gave it a try. The driver test is a bit "cleaner" signal wise this time, but I still have exactly the same issue. The motors make a whiz/hum when I press the arrow keys, or type in a movement, but nothing physically moves . Maybe I have the wiring wrong? I thought if that was the case, I'd get an error light on the G540 though, which I don't have. Argh...

Hi Paul,

I had all sorts of issues as my ISP had to change my site to a new server. I can't find the email you sent.

Have you tuned the motors in Mach3 yet? You do that from the motor tuning tab. Also check that the Gecko profile setup matches the parallel port pins in the G540 manual.

Cheers,

Peter.

Hi Peter,
No worries about the lost email - sorry to hear your having troubles with your site

I have just re-checked the pin settings again, which match those shown on the G540. As for the motor tunning, I am using m12 rod and used the following values in Mach3:
Steps = 10400, Vel = 10 & Acc = 7 for all axes (units set to inches).

Regards,
Paul

Hi Paul,

This is really strange, The G540 is meant to be plug and play.

Check the pulse width in the motor turning tab. Try setting it to 5uS

If that doen't help, can you send my your xml profile file and I'll try it here and see if I can find anything.

Cheers,

Peter.

Hi Peter,

Tell me about it!!
I tried changing the pulse width - still no go.
It's really strange, if I hold the motor in my hand, I can feel it vibrate and make a noise when I jog in Mach3, but no physical movement. All three motor are the same. If I change the motor tuning, it has an effect on the "pitch" of the hum!.
I have attached my config file - I had to rename it to be able to upload it.
Thanks for you help here Peter.

Regards,
Paul

Hi Paul,

I should be able to set it up and test it later this afternoon.

Cheers,

Peter.

Thanks Peter,
I'm hope you find something wrong with the config file, so it will be an easy fix!

Cheers,
Paul

Success - I have motor movement!
I unsoldered the resistor I put across pins 1 - 5 of the DB9 plug. Once I did that, the motors turned!?.
So what did I do wrong? I'm guessing I used the wrong resistor?
I have attached a pic of the pack I used.
Can someone point me to the correct one I should use please?

Regards,
Paul

this is from the gecko websites G540 manual:

STEP 4: CONNECT MOTORS

Wire your motors to the included DB9 solder cup and secure the backshell connectors. If your motors are rated below 3.5A you must use a current set resistor across PIN 1 and PIN 5. The resistor is calculated by taking the current in amps and multiplying by 1000. If your motor is rated at 2.8A per phase you will have to use a 2.8K 5% 1/4W resistor. If your motor is rated at 3.5A or above you can safely not use a current set resistor; however, your G540 will not go into current standby mode which will result in increased motor heating.

At this point you should have holding torque on the motors and a green LED lit. If you do not then the motor is wired incorrectly or is damaged.

Looking at Peter's website, the 387 oz/in motors he sells are rated at 3.5A.

To me (if I'm reading this correctly) you shouldn't need a resistor at all.
Can someone (hopefully Peter or someone with far more knowledge than me) can confirm??

Regards,
Row.

Hey Row,

Thanks for your input.
That's how I read it too. I'm not sure how much hotter they get without the resistor.
I thought I'd be on the safe side and add one anyway.
Anyone running these motors without the resistors have any comments?

Cheers,
Paul

A 3R3 (3.3 ohms) is almost the same as a dead short.

Originally Posted by Bob Willson

A 3R3 (3.3 ohms) is almost the same as a dead short.

Yea bob's right if your using 3.3ohm thats where your problem lies.

You can also run the motors without a resistor and they will run at 3.5A, the resistor is used to reduce the current during standby.

I normally solder 2 resistors together in series to get the correct value, ie. a 2K + 1.5K or whatever I have avaliable, you can buy them from jaycar (1/2 Watt resistors)

You might as well be speaking Chinese Bob!
I asked the guy in Jaycar for a 3.5k, 0.25w, 5% resistor and thats what he gave me! .
Can anyone point me to something suitable on the Jaycar website?

Thanks Chris - I'm was just concerned about overheating the motor though. I guess I'll run them without and see how we go.

Regards,
Paul

Originally Posted by Woodlake

You might as well be speaking Chinese Bob!
I asked the guy in Jaycar for a 3.5k, 0.25w, 5% resistor and thats what he gave me! .
Can anyone point me to something suitable on the Jaycar website?

Thanks Chris - I'm was just concerned about overheating the motor though. I guess I'll run them without and see how we go.

Regards,
Paul

3K3ohm 1/2 Watt 1% Metal Film Resistors - Pk.8 - Jaycar Electronics

3.3K ohm is the closest they have in a single resistor.