Powerflex 525 overwrites accel/decel parameters...

[HDeno 0]

Hi guys,

 

  I have a strange problem.. I got an application with 10 PF525 all pretty much doing the same job...  BUT, one of them has a weird problem. When I do a power cycle, the Accel Time 1 and Decel Time 1 get overwritten with values of 0.25 second instead of the 1.00 second I entered in the parameters...  This then creates faults as the VFD will trip under such a short decel time.. If I change it manually back to 1.00 I am good to go until next power cycle, where it reverts to 0.25 again...   I communicate to them using Ethernet IP to do that start/stop, but I do not send any parameter config through Enet....

  Anybody has an idea as to what might be happening here?

 

Thanks

Edited 4 Mar 2016 by HDeno

[Donovanr 0]

Are you controlling bits 8, 9,10,11 of the controlword from the PLC? 

In particular, you can set the acceleration rate by setting bits 8 and 9 as follows:

bit 8 = 1 and bit 9 = 0 set the Accel Rate toAccel Rate 1 (fixed in parameter P041 [Accel Time 1])

bit 8 = 0 and bit 9 = 1 set the Accel Rate toAccel Rate 2 (fixed in parameter P442 [Accel Time 2])

You can set the deceleration rate by setting bits 10 and 11 as follows:

bit 10 = 1 and bit 11 = 0 set the Decel Rate toDecel Rate 1 (fixed in parameter P042 [Decel Time 1])

bit 10 = 0 and bit 11 = 1 set the Decel Rate toDecel Rate 2 (fixed in parameter P443 [Decel Time 2])

What version of firmware do you have on all 10 drives? Right click on the drive when in RSLinx and select properties.