CNC Milling Machine: PWM Control Problem

[phyllis_ave]

Hi there,

I have a setup with MACH3 where it should send a PWM signal, which will be converted by a digispeed board into a 0-10V analogue signal for my motor drive, but all I am getting out of the digispeed board is 0.1V max.

I've tried adjusting the attenuation trimpot on the digispeed board but it doesn't seem to do anything

Does anyone know what could be wrong here?


Just to be make sure I am testing the right thing, if the output from the digispeed board isn't connected to anything it should still send out the analogue signal, correct? I am just plugging my multimeter directly into the output on the digispeed board and getting the 0-0.1V readings.

Thanks in advance,

Phil

[jalessi]

What model breakout board do you have?

[GaryCorlew]

Don't have a digispeed but with a cnc4pc board the pulse width affects the voltage output, so you may want to take a look at that. I have mine at 5

[phyllis_ave]

jalessi: I have the C10 model board from CNC4PC.

Gary: When you say your pulse width is 5 what do you mean? Is there a setting in MACH3 to control this?

[jalessi]

Do you have a instant messenger?

Jeff...

[jalessi]

What model Digispeed do you have?

[phyllis_ave]

I have the digispeed DC-03.

I have the digispeed connected just as it says in the user guide, with the 5V and GND from the breakout board and the PWM from the output pin assigned in MACH3. I'm also running the relays on the board to enable and set the direction of the spindle.

I have windows messenger - phyllis_ave@hotmail.com - but I won't be online for a while since its past midnight here and I'm about to go to bed.

[phomann]

Hi,

I just noticed this thread. Did you sort out your issues with the DC-03?

Cheers,

Peter.

[LeeWay]

There are lots of settings in Mach 3 that have an effect on spindle control. The manuals Peter has are pretty darn good though with screen shots. Can't get better than having Peter answer directly though.

[phyllis_ave]

Yes I am still having trouble with the DC-03, although I am pretty new at this so I've probably just overlooked something really simple.

At the moment the DC-03 shows the double flash (PWM mode) but I'm not getting the output voltage I need.

I think my problem is probably in MACH3 but I can't seem to find what I've done wrong.

Also here's my wiring setup for the DC-03 just in case I've done something really stupid here.

Ana - none
+5V - +5V from breakout board
RL2 - CCW output from BoB
RL1 - Enable from BoB
Sig - Spindle Step from BoB
Gnd - Common from BoB

AV+ - none
Vout - DC control voltage (should be +0-10V)
AGnd - DC control voltage ground
Relay outputs are connected to the switches in my motor controller

Note: The relays are working fine, its just the speed control voltage that I'm having trouble with.

[phomann]

Yes I am still having trouble with the DC-03, although I am pretty new at this so I've probably just overlooked something really simple.

At the moment the DC-03 shows the double flash (PWM mode) but I'm not getting the output voltage I need.

I think my problem is probably in MACH3 but I can't seem to find what I've done wrong.

Also here's my wiring setup for the DC-03 just in case I've done something really stupid here.

Ana - none
+5V - +5V from breakout board
RL2 - CCW output from BoB
RL1 - Enable from BoB
Sig - Spindle Step from BoB
Gnd - Common from BoB

AV+ - none
Vout - DC control voltage (should be +0-10V)
AGnd - DC control voltage ground
Relay outputs are connected to the switches in my motor controller

Note: The relays are working fine, its just the speed control voltage that I'm having trouble with.

Hi,

First thing to do is make sure that the DC-03 is in the correct mode. There are 2 jumpers (JP3)that set the mode.

The status LED on the DC-03 indicates the mode that the DC-03 is in, when the unit is powered up.

For PWM mode, the status LED will flash twice on powerup before going into the lazy double flash. The manual explains these modes.

Also, have a look at this engineering not. It shows the position of the mode jumper for PWM mode.

http://www.homanndesigns.com/EN009_V2.pdf


The double lasy flash indicates that their is no PWM signal from Mach3 at the DC-03 'Sig' input.

The manual also has a step by step Quick Start set-up guide. If you follow it, tell me at which point you can't get it to work.

Cheers,

Peter.

[phyllis_ave]

Ok I do get the double flash on startup then the lazy double flash after that. Also I have the JP1 jumper on the dc/dc side and I am not using the AV+ pin. Is this correct?

It seems like there is some control coming from MACH3 as the voltage does change when I change the spindle speed, however it only varies from around 0-0.1V instead of the 0-10V that I should be getting.