PowerFlex 753 Faulted but Not Faulted

terry56

Member
Join Date
May 2010
Location
California
Posts
45
I have a weird one Folks!
• The HIM Module does not show any fault.
• The VFD Drive in the panel is showing the STS LED blinking RED.
• I checked the Fault logs in the drive. It does not show any fault.
• The Drive shows it is “Not Ready”.
• Fault History only shows Power Up/Down Faults.
• Reset will not clear the STS LED blinking RED.

I am off site now , but anyone seen this before?
 
Are you sure the STS led is flashing red? The light that they call yellow, looks more orange/red than yellow to me, and could be confused for red. The flashing yellow is a start inhibit, which could be as simple as the stop-cf is off. Look at parameter 933.
 
If I remember correctly, flashing red is "stop asserted" meaning wiring or logic is sending a stop command. When the stop command is removed in the logic, it will flash yellow waiting for a start command.
 
Yellow

  • Flashing; Drive is not running, a start inhibit condition exists and the drive cannot be started. See parameter 933 [Start Inhibits].

  • Steady; Drive is not running, a type 1 (user configurable) alarm condition exists and the drive continues to run. See parameters 959 [Alarm Status A] and 960 [Alarm Status B].
Red

  • Flashing; A major fault has occurred. Drive will stop. Drive cannot be started until fault condition is cleared. See parameter 951 [Last Fault Code].

  • Steady; A non-resettable fault has occurred.
Red / Yellow

  • Flashing Alternately; A minor fault has occurred. When running, the drive continues to run. System is brought to a stop under system control. Fault must be cleared to continue. Use parameter 950 [Minor Flt Cfg] to enable. If not enabled, acts like a major fault.
But my guess is what proof said. It's a "dark yellow" and someone is seeing that orange as red. Wouldn't be the first time. When you see the real red color the difference is obvious, but if you only see the "dark yellow", some people assume that's an orange-ish red. it's kind of a common consequence of using a tri-color LED.
 
I saw the yellow light. I changed a drive and didn't set the safety jumper on the new drive.
 
Not likely to help, but I had an interesting failure one time on an SCR Bus Supply feeding a group of PowerFlex 700s drives. Because my family and friends don't care for my boring stories, but some of you might, I'd like to share.

I walked into work one night, and this particular line had been down for several hours. The SCR Bus would not power up, and would only show a RED fault light, no fault code. I continued troubleshooting. Now, nobody ever really wants to change out these 150 lb. drives/inverters/power supplies, because it's actually a pain in the butt trying to strap, winch, cart, these units into a control cabinet, with little room, which ultimately ends up with the biggest 2 Bubba's just man-handling the thing into position while you squeeze between them and say "down and to the left," while trying to start the first screw.

Especially if it does not solve the problem. So, if you're going to change one, you better at least have a reason other than "I don't know what else to do." So, I can respect the previous shifts position.

So I'm trouble-shooting and following the manual verbatim, and the manual keeps stating to "VIEW THE FAULT CODE AND TAKE RECOMMENDED ACTION." The problem was, there was no fault code displayed. Only a RED fault LED.

Now, I wish I could say I solved this because I'm smart, but the reality is, after about two hours of chasing my tail, I powered up the cabinet, and just barely noticed a super tiny twinkle of a spark on the front of the power supply. Upon further inspection, I noticed a microprocessor board, about 4 inches by four inches, that had a super tiny transformer/reactor of sorts, with a hair thin wire burned open. I busted open the crate with the spare SCR Power Supply. Removed the four 2mm screws and the ribbon cable on the microprocessor, swapped it into the existing power supply and powered up without issue. Run The Line! That board apparently handled the fault codes and power up sequence.

Felt like a hero, right? Especially because I didn't need to swap out the whole power supply.

That night I got the work order to "Replace the entire power supply unit with the spare/ and swap the microprocessors back, because we're not convinced that was the root cause."

Point is, as rare as it is, don't forget there can be a problem with the fault handler as well.
 
Yellow

  • Flashing; Drive is not running, a start inhibit condition exists and the drive cannot be started. See parameter 933 [Start Inhibits].

  • Steady; Drive is not running, a type 1 (user configurable) alarm condition exists and the drive continues to run. See parameters 959 [Alarm Status A] and 960 [Alarm Status B].
Red

  • Flashing; A major fault has occurred. Drive will stop. Drive cannot be started until fault condition is cleared. See parameter 951 [Last Fault Code].

  • Steady; A non-resettable fault has occurred.
Red / Yellow

  • Flashing Alternately; A minor fault has occurred. When running, the drive continues to run. System is brought to a stop under system control. Fault must be cleared to continue. Use parameter 950 [Minor Flt Cfg] to enable. If not enabled, acts like a major fault.
But my guess is what proof said. It's a "dark yellow" and someone is seeing that orange as red. Wouldn't be the first time. When you see the real red color the difference is obvious, but if you only see the "dark yellow", some people assume that's an orange-ish red. it's kind of a common consequence of using a tri-color LED.
Is there a way i can do a GSV to get the status of parameter 933 (specifically bit 7)? I would like, using the "drive ready" feedback is not enough to know if there is a STO issue...

Thanks
 
GSV No, but I think you can get the parameter value from a MSG.
Try a MSG With:
Type: CIP Generic
Service Type: Get Attribute SIngle
Class: 9f
Instance 933
Attribute 9


Save it to a DINT tag.
The MSG Path should be just the drive instance.
 
GSV No, but I think you can get the parameter value from a MSG.
Try a MSG With:
Type: CIP Generic
Service Type: Get Attribute SIngle
Class: 9f
Instance 933
Attribute 9


Save it to a DINT tag.
The MSG Path should be just the drive instance.

Wow, this works! Thanks so much!
 

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