powerflex 755 fault 926

[Cld0033]

Has anyone had any luck resolving issues with the power flex 755 faulting with the 926-fault code. I have read that switching to revision 14.0 has helped, but my boss unfortunately does not want us to do that. One of our two drives are faulting every hour on the hour.

 

[robertmee]

That's your best option. It's what Rockwell recommends. There is a bug in ver 16 fw. Knowledge base says to downflas to 14.005

 

[lmscar12]

We called Rockwell about this several months ago before they had started recommending downflashing. They said it's caused by "excessive network traffic." Well we ended up wasting a bunch of time diagnosing with Wireshark and disabling various network comms, only to find that it didn't help. In the end Rockwell told us to buy their non-embedded ethernet card for Powerflex 750-series drives to fix the issue. I suggested flashing down to version 14 and they said "yeah that might work." Lo and behold, it sure did. No purchase necessary.

So as I see it you've only got two options: buy a new card (~$500) and wait for it to arrive, or downflash, which takes about 15-30 minutes.

Why is your boss so resistant to it? Can he point to any benefit that version 16 gives over version 14?

 

[robertmee]

We called Rockwell about this several months ago before they had started recommending downflashing. They said it's caused by "excessive network traffic." Well we ended up wasting a bunch of time diagnosing with Wireshark and disabling various network comms, only to find that it didn't help. In the end Rockwell told us to buy their non-embedded ethernet card for Powerflex 750-series drives to fix the issue. I suggested flashing down to version 14 and they said "yeah that might work." Lo and behold, it sure did. No purchase necessary.

So as I see it you've only got two options: buy a new card (~$500) and wait for it to arrive, or downflash, which takes about 15-30 minutes.

Why is your boss so resistant to it? Can he point to any benefit that version 16 gives over version 14?

FYI, I just had an install of 18 PF755s with the external ethernet modules. Same exact problem until I downflashed to 14.

 

[Cld0033]

Well finally convinced her to let me downflash, and sure enough no faults since.

 

[JankyPLC]

I'll add to this. Same issue in a panel with an isolated switch, a drive, an HMI, and a PLC. Got this fault when we replaced drive. New drive had v16. Great people on here suggested downflashing to 14, problem solved. Actually had to do this to two other drives. The fact that Rockwell hasn't released a v16.1 or something to resolve this is insane... but typical.

 

[robertmee]

I'll add to this. Same issue in a panel with an isolated switch, a drive, an HMI, and a PLC. Got this fault when we replaced drive. New drive had v16. Great people on here suggested downflashing to 14, problem solved. Actually had to do this to two other drives. The fact that Rockwell hasn't released a v16.1 or something to resolve this is insane... but typical.

They in fact just announced mature active status for 755s with no additional fw releases.

 

[Cld0033]

There is a v20.0 that supposedly fixes the issues, but it is only compatible with series B Frame 7 and below