Motor control

[can]

Hi. Has anybody tried to control the speed of an ac servo motor by using the analogue output to give a voltage to the motor driver? I currently have a motor driver that accepts 0-10vdc as analogue input. I want to use the analogue output of 0-5vdc to control it. The question is that if I activate function setDAC 1,4096, will the motor driver immediately run at full speed? Or should I write a function to accelerateor decelerate the motor by varying the output voltage?

Regards
Can

[support]

A servo motor should have its own feedback loop so you can simply supply it with a stable voltage it needs.

Since the servo motor driver requires 0-10V you need to give it 10V to run at full speed. You can use the F1616-BA which has built-in 0-10V analog outputs.

If you supply 5V to the servo motor it is most likely going to run only at half speed (depend on what the spec is).

[can]

Hi. So do I have to varies the DAC from 0 to 4096 if i want the motor to accelerate smoothly?

Regards

[support]

I don't think so, but there is nothing to stop you from doing it. The best is to test the dynamic of your system by using a step input first (i.e. apply the voltage in a single step) and if the response is not desirable you can then give it a slope which is easy to do with our PLC.

[can]

Ok. Thanks for the quick reply. Will try that out.

[can]

Hi. I have another question. If the servo motor driver output is giving positional signal by A, B, and Z phase, is there anyway a 888 will be able to determine the position by reading the signal?

Regards

[support]

Are the A B and Z signals analog? If these signal are within the range of the PLC's analog inputs you can certainly read them using the ADC(n) statement.