Setup:
SLC 5/05 with three 1747-SN Modules in Main Rack. Two of the three modules are controlling about 23 Powerflex 70 Drives (10 on one module, 13 on the 2nd). Baud at 230K, proper resistors installed. Powerflex 70's are all installed in a Centerline MCC.
I have the drives all configured as 1/4 rack, so I have to pass the reference via BTs. I read the speed feedback and amps. So, all the BTW instructions pass 1 word (limiting overhead), and all the BTRs read 6 words (fdbk + amp + spare).
I started with standard bidirectional BTR/BTW using bits 12 and 13 to fire the BTRs and BTWs. I started running into what I feel are 'overload' issues, so to reduce the # of BTR/BTWs firing I did the following:
A BTR/BTW only fires if the drive is on-line
A BTW only fires if the current speed is different from the setpoint (only on Setpoint change) and if the drive has a start command.
Now to the problem: The BTRs seem instantaneous on updating. If I give the drive a start/stop command, I can see the speed feedback and amps ramping up/down. The BTWs however seem to be another story. It takes up to around 3 to 5 seconds for the drive to accept a new speed reference. That I can live with. However, there are a few drives that it might take upto 5 MINUTES before the reference finally shows up at the drive. To diagnose, I've done:
Monitored the .ER bit and the Error Code: I get no errors on the BTR or BTW instructions. The # of transmitted words is either 0 or matches (toggles). The DN and EN bit are also toggling as expected.
Tried different approaches of when to fire the BTR/BTW instructions with little difference.
Lastly, I decided to shut off all the drives except for a few. Suddenly, the drive that was taking 5 minutes to update the reference was now updating with a few seconds. Turn all the other drives back on, and it goes back to 5 minutes. That means it could be back to BTR/BTW overload or maybe noise from all the drives being on? Remember, the BTR/BTW only fires when the drives are on-line (using the M file status word).
The worse drive is the next to last drive in the string. It's BTR/BTW is somewhere in the middle of all BTR/BTW operations. So, I am pulling my hair out on this one.
Any suggestions on where to troubleshoot next? Is there anything I can look at that would be indicative of noise on the RIO link causing lost transmissions (EDIT: I found the retry counters, so I'll look at them in the morning)? Again, the actual BTR/BTWs are not in error. I'm going to look at the routing of the blue hose since it does sake its way around the MCC and is very likely near many 480VAC feeds.
What about slowing down the baud? I do have an I/O rack hanging off the module with 10 drives, but I don't think 56K would be a big deal. I know typically in noisy environments, lower baud sometimes means lower retries.
Next time, its ControlNet or nuttin on SLC, no matter what the customer says
SLC 5/05 with three 1747-SN Modules in Main Rack. Two of the three modules are controlling about 23 Powerflex 70 Drives (10 on one module, 13 on the 2nd). Baud at 230K, proper resistors installed. Powerflex 70's are all installed in a Centerline MCC.
I have the drives all configured as 1/4 rack, so I have to pass the reference via BTs. I read the speed feedback and amps. So, all the BTW instructions pass 1 word (limiting overhead), and all the BTRs read 6 words (fdbk + amp + spare).
I started with standard bidirectional BTR/BTW using bits 12 and 13 to fire the BTRs and BTWs. I started running into what I feel are 'overload' issues, so to reduce the # of BTR/BTWs firing I did the following:
A BTR/BTW only fires if the drive is on-line
A BTW only fires if the current speed is different from the setpoint (only on Setpoint change) and if the drive has a start command.
Now to the problem: The BTRs seem instantaneous on updating. If I give the drive a start/stop command, I can see the speed feedback and amps ramping up/down. The BTWs however seem to be another story. It takes up to around 3 to 5 seconds for the drive to accept a new speed reference. That I can live with. However, there are a few drives that it might take upto 5 MINUTES before the reference finally shows up at the drive. To diagnose, I've done:
Monitored the .ER bit and the Error Code: I get no errors on the BTR or BTW instructions. The # of transmitted words is either 0 or matches (toggles). The DN and EN bit are also toggling as expected.
Tried different approaches of when to fire the BTR/BTW instructions with little difference.
Lastly, I decided to shut off all the drives except for a few. Suddenly, the drive that was taking 5 minutes to update the reference was now updating with a few seconds. Turn all the other drives back on, and it goes back to 5 minutes. That means it could be back to BTR/BTW overload or maybe noise from all the drives being on? Remember, the BTR/BTW only fires when the drives are on-line (using the M file status word).
The worse drive is the next to last drive in the string. It's BTR/BTW is somewhere in the middle of all BTR/BTW operations. So, I am pulling my hair out on this one.
Any suggestions on where to troubleshoot next? Is there anything I can look at that would be indicative of noise on the RIO link causing lost transmissions (EDIT: I found the retry counters, so I'll look at them in the morning)? Again, the actual BTR/BTWs are not in error. I'm going to look at the routing of the blue hose since it does sake its way around the MCC and is very likely near many 480VAC feeds.
What about slowing down the baud? I do have an I/O rack hanging off the module with 10 drives, but I don't think 56K would be a big deal. I know typically in noisy environments, lower baud sometimes means lower retries.
Next time, its ControlNet or nuttin on SLC, no matter what the customer says
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