UC300 Analog output voltage

[Delco]

I have a small mill I want to interface a uc300 to . the Spindle speed control needs a 0-5V signal to operate it .

If I set the spindle parameters as min pwm duty cycle to 0% and max pwm duty cycle to 42% will that limit my output voltage to 0-5V ?

[ger21]

I've done that to use 0-5V

[cncdrive]

Yes. But if the spindle controller is sensitive to overvoltages then put in a series resistor and a Zener diode between the signal and gnd (e.g. 5.6V zener) to make sure to block the voltage upper limit at 5.6Volts. Just so missconfiguration in the PWM max. duty cycle then cannot damage the spindle controller, because the zener diode will block the voltage at 5.6Volts.

[Delco]

Trying to get my head around how the calibration of the output actuallworks.

So if I have spindle min % at 10 and max% at 80 then it can output a voltage between 1.2V and 9.6V and the speed velocity min would be rpm that 1.2V produces and the spindle velocity max would be the rpm at 9.6V .

Is that correct ?

Or is there a procedure for calibration of it ,

[ger21]

So if I have spindle min % at 10 and max% at 80 then it can output a voltage between 1.2V and 9.6V and the speed velocity min would be rpm that 1.2V produces and the spindle velocity max would be the rpm at 9.6V .

Is that correct ?

I believe so, provided you are getting 12V at 100% and max RPM.

[cncdrive]

Delco, Yes thats correct, that is how it exactly works.

[Battwell]

something i find strange. is if minimum pwm is set then this is output all the time. (in my mind this should only be on during spindle run)
minimum pwm is always output even when the spindle is off.
reason?

[Delco]

something i find strange. is if minimum pwm is set then this is output all the time. (in my mind this should only be on during spindle run)
minimum pwm is always output even when the spindle is off.
reason?

Wonder if this is a issue for me , I have had 2 UC300s fail in this last month on 2 different machines - they loose analogue output to VFD , both had 20% as min PWM . Both machines are powered on 24/7 and have been running for 6 months and 10 months respectfully , they have used everyday without issue.

Only thing wired to analogue port is the Analogue 1 out to VFD A01 and the Analogue Gnd to VFD GND.

I have good 5V to UC300 and the UC300 still works but nothing on analogue port.

[Delco]

After further checking the 2nd failure looks to be not a failure but a bad connection on a analogue pin . Because the failure mode seemed the same I and only a week apart I wrongly assumed it was same fault just swapped out the UC300 out without fully testing and because the connectors had to come of and be reseated It worked fine with the new UC300 . Came back to shop and dropped what I thought was a faulty UC300 in a working machine to do some tests and its working fine .