What is the difference between Ready & Active

Hello.

I have some PowerFlex drives which I wish to control via ethernet. But I am wondering what is the difference between the drive Ready and drive Active signals/status?


Thank you

Ready means drive is ok, Active means drive is controlling motor speed, of course is still active.

Thanks for the reply.

In my PLC ladder I monitor both Ready and Active.

It seems they are both False until I give the Start signal, I don't remember seeing Ready as being True when the drive is ready but not running the motor.

I was hoping to use Ready just for that - to know when the drive was ready, no faults.

Bit 0 “Ready” – Condition is true if there are no start inhibits indicated by P933 [Start Inhibits].

Bit 1 “Active” – Condition is true if drive is modulating

This is for PF 755/753, but for others (PF again) is the same

It seems they are both False until I give the Start signal, I don't remember seeing Ready as being True when the drive is ready but not running the motor.

Click to expand...

Your PLC program may not be showing the actual VFD status signal, but rather the status signals modified by the operator Start and Stop signals. In other words, when the drive has not been started, the programmer may have chosen to show the drive as "not ready". If your status signals are being retrived though a communications cable to the drive, then the true drive status signals should be available.

Check the state of the STOP command bit. Is your command logic holding the STOP bit true whenever the START bit is not commanded ?

The best method is to hold STOP true until "Running" goes false. This verifies that the drive has stopped as commanded.

Which exact model of PowerFlex are you using ? The 4-class might work a little differently than the 7-class.