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Author Topic: PWM and Digispeed  (Read 5926 times)

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Offline jimpinder

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PWM and Digispeed
« on: August 06, 2008, 01:29:47 PM »
My speed control seems to have stopped working.

As far as I can see, I have all the correct ticks in the boxes - i.e. spindle step, active, spindle motor output, pwm control, use spindle feedback in sync mode.
My index is still working and the spindle speed is tracked when I operate it manuall.
I seem to have a PWM signal coming out of  pin 16, which I can measure with my mulrimeter, and it alters as I vary the speed using the S command.
I have the digispeed enable at 0volts.

Anything else I have forgotten before I declare my digispeed dead ???  I am at a loss :'( :'(
Not me driving the engine - I'm better looking.

Offline Hood

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Re: PWM and Digispeed
« Reply #1 on: August 06, 2008, 02:01:18 PM »
Presume you have checked the voltage going out of the Digispeed to your VFD is non existant?

Hood

DaveDoesIT

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Re: PWM and Digispeed
« Reply #2 on: August 06, 2008, 08:51:00 PM »
I seem to have a PWM signal coming out of  pin 16, which I can measure with my mulrimeter,

Hi Jim,

The multimeter may not be telling you much. You really need an oscilloscope to make sure the PWM is there. Noise on the PWM output would look the same as varying duty cycle on PWM.

Maybe an old analog multimeter would be better than a digital, but even then not conclusive as the voltage should not be varying just the duty cycle. The analog would dampen the pulses significantly. The analog needle would just wobble at different rates that may be visible. Just guessing, never tried it. Old scopes 6M and 10M can be had for peanuts these days.

Dave
Re: PWM and Digispeed
« Reply #3 on: August 06, 2008, 09:14:02 PM »
My speed control seems to have stopped working.

As far as I can see, I have all the correct ticks in the boxes - i.e. spindle step, active, spindle motor output, pwm control, use spindle feedback in sync mode.
My index is still working and the spindle speed is tracked when I operate it manuall.
I seem to have a PWM signal coming out of  pin 16, which I can measure with my mulrimeter, and it alters as I vary the speed using the S command.
I have the digispeed enable at 0volts.

Anything else I have forgotten before I declare my digispeed dead ???  I am at a loss :'( :'(

Hi Jim,

You have a DC-01, correct?

Has the DigiSpeed been working in the past, or is this the first installation?


The status  LED on the DC-01 will tell you if the DigiSpeed is working. 

1. With power applied to the DigiSpeed, and spindle not turned on via Mach3, the LED should be solid red.

2. With power applied to the DigiSpeed, and spindle  turned on via Mach3 with speed set to zero , the LED should do a double slow flash.

3. With power applied to the DigiSpeed, and spindle  turned on via Mach3 with speed set to a non zero value say 1000rpm , the LED should do a continuous flash.

If all three steps work them the logic side of the DigiSpeed is OK.

Next set the spindle speed to about 50% and using a multimeter, measure the voltage on the DC-01 Yellow lead with respect to theDC-01  black lead. This is with the speed controller powered on. Be careful as these leads will have 90+ volts on them.

Let me know what you find.

Cheers,

Peter.






----------------------------------------------------
Homann Designs
http://www.homanndesigns.com
email: peter at homanndesigns.com

Offline jimpinder

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Re: PWM and Digispeed
« Reply #4 on: August 07, 2008, 12:47:48 PM »
I have two set ups - my machine is a lathe with a milling head. I was using the lathe and could not get the Omron inverter to react to the speed input - command S. The flash is only the slow double flash

Funnily enough - I was up in the early hours of this moring and fired it up in milling mode, and for a short time (no more than five minutes) the led was the fast flash. I saw this and changed my Omron to take orders from the Digispeed, but then the thing reverted to the slow double flash.

Peter - If you are looking at this - a screw down cable attachment would be preferable - my old eyes have difficulty soldering the tiny wires to a six pin mini din.

I am going to fiddle with it a little more and I will get back to you. Either the Digispeed goes down when it gets warmed up, or there is something wrong in the Mach output. Yes it has worked before - very effectively.
Not me driving the engine - I'm better looking.
Re: PWM and Digispeed
« Reply #5 on: August 07, 2008, 08:44:08 PM »
Hi Jim,


When the DC-01 is first powered up, is the status LED RED? Check that it is not yellow. That is the red and green LEDs in it are not both turned on. It may be powering up into serial control mode.

The idea of the DC-01 is to use a minidin cable between it and the minidin breakout board that has screw terminals on it. I can send you one if it helps.

Also you can check that the digital part of the DC-01 is working correctly without the VFD connected. The status led tells you what is going on.

Cheers,

Peter.


----------------------------------------------------
Homann Designs
http://www.homanndesigns.com
email: peter at homanndesigns.com