Powerflex 700S2 / 2 encoder problem

hi everybody,

I have a small problem with a powerflex 700 S2 Drive in conjunction with 2 encoders (2nd encoder option card is mounted).

encoder 0 is mounted on the shaft of a conveyor
encoder 1 is mounted on the main motor of a machine.

The goal is to run the conveyor with exactly the same speed as the main motor of the machne.

I had everything mounted in my office for testing and all worked fine (autotune etc.). I tested the system with a drilling machine (encoder 1) and encoder 0 mounted directly to the test drives shaft. as already said, all worked excellent.

Now i am on site and have a problem.

encoder 0 is now mounted on the shaft of the conveyor (not the motor) with a gearbox between.

Autotune now fails because the speed feedback is not correct (this is true, it is of by the gearbox ration (ca. 5.2 Factor)).

I cannot find any way to tell the powerflex 700 Drive to multiply the encoder signals with about 5.2.

encoder 0 is configured as Speed Feedback Signal Primary
encoder 1 Speed Signal is linked to Parameter 10 (Speed Signal).

Is there any way to fix this ?

thank you in advance

greets

You must have to tell the drive what the Pulse Per Revolution rate is for each encoder somewhere in the parameters. On the encoder with the gearbox, multiply the actual PPR times the gearbox ratio and enter that for the encoder PPR.

hi,

no, that is too easy . The Powerflex only allows me to enter predefined ppr values. These valid settings are written in the manual. I tried it anyway and it does not work, the drive does not start anymore with these settings.

greets

As a temporary fix, you may be able to configure the drive for sensorless vector mode so that it does not need encoder 0 as a speed feedback signal.

This may affect the performance too much for you application but is worth a try.

I don't have the PF700 manuals available so I can't be specific how to do this.

Paul