Help with servo spindle control.

[Chattygt]

Hello, I'm struggling with spindle control through my pmdx board.


The machine uses a pmdx-122 to connect to mach3. I have managed to get each axis moving properly but I am struggling with the spindle.

It is a SEM Servo Spindle motor (factory from what I gather) connected to an Advanced Motion Controls B25A20 Driver.

As of right now the driver is connected to the pmdx using the relay (connected to inhibit in signal on driver and the negative output on signal isolator) and pin 14 (spindle direction) which is connected to a SI-240D signal isolator, which is set up to convert the 0-5v to 0-10v.

For the life of me I can't figure out how to make the spindle run. My best guess that I have found is that the inhibit wire when grounded disables the spindle. But when not grounded should enable the spindle (+5v as the manual states). When probing the inhibit it only has 4.30v. I believe that's why it isn't running but I could be wrong.

Could this driver be set up in my pmdx 122 as a fourth axis and control it as the spindle ? Or is it wired the correct way?

Thanks.

[12strings]

From what I can tell, the SI-240D expects an analog input signal.  The closest that you can get from the PMDX-122 is a PWM signal from Mach3.  If the SI-240D has any kind of integrating capacitor circuit inside, that could work.  But I don't see any mention of it accepting a PWM input.

The 0-5V output from the PMDX-122 is a digital output, i.e. either close to 0V or close to 5V.  Nothing in between.

If you had  PMDX-126, you could add a PMDX-107 to drive the servo controller signals.  With a PMDX-122, I am not sure you can get there.  Well maybe so - look at the PMDX-407.  There appears to be a PMDX-407-S version that claims to work with the PMDX-122.  If that is available, you shouldn't need the SI-240D as the 407 should connect directly to the 0-10V analog input on the servo driver.

[Chattygt]

Thank you for the reply. I have found another topic  relating to a pmdx 122 and a 407s.

I may go this route to ensure I have proper spindle speed control using pwm signal. Right now from what I can gather the spindle is being turned on at max rpm (can be changed from a high and low gear by the operator). Spindle speed control would be ideal.