Random DeviceNet "Port 5 Adaptor " Fault on various PowerFlex 70 Drives in Panel

Rob S.

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Random DeviceNet "Port 5 Adaptor " Fault on various PowerFlex 70 Drives in Panel

Good Evening ,

We have a machine with about 17 - PowerFlex 70 Drives . The PLC is a SLC 500 5/05 CPU and has a 1747-SDN DeviceNet Module . For the last several months we have had random DeviceNet Communication Faults on about 5 of these drives in this panel. The fault displayed on these drives is.....
" F 75 Port 5 Adaptor " , and the 1747-SDN has a '78" fault on it. With your all's experience , what would be the main cause of this fault on different drives ? I could see if it was just one drive , but it is different drives in this panel . Could it be the DeviceNet network ? Possible wiring , voltage drops , etc. ?

Also , what is the best way to upload the scanlists from a 1747-SDN ?
I imagine the scanlists are actually in the 1747-SDN , correct ? Also , what is
a 1770-KFD Communication Module ? What is the best way to communicate with a 1747-SDN ?

Thanks so much for your help , like always.
 
...For the last several months we have had random DeviceNet Communication Faults on about 5 of these drives in this panel. The fault displayed on these drives is.....
" F 75 Port 5 Adaptor " , and the 1747-SDN has a '78" fault on it. With your all's experience , what would be the main cause of this fault on different drives ? I could see if it was just one drive , but it is different drives in this panel . Could it be the DeviceNet network ? Possible wiring , voltage drops , etc. ?

As you likely already looked up, the scanner fault message of 78 for the affected drives translates to 'scanner can't see these drives'. 'F 75 Port 5 Adapter' translates to the Powerflex 70 dpi port losing communication to whatever control network you use - devicenet in this case

How is your devicenet set up? Are you using flat cable or the round trunk cable? Is the scanner in the middle of the network or on one end?

Since you are having problems in one panel, I would check the first drop connector from the SDN into the panel. Or if you are using the multi-port drop connectors, the connection into it. If you are at the stage to start changing stuff out, that's where I would start. It should not be a particular drop cable - as that would affect only one drive. The main trunk, or a trunk connector where everything on the network downstream is having the issue - that's were I'd start.

Also , what is the best way to upload the scanlists from a 1747-SDN ?
I imagine the scanlists are actually in the 1747-SDN , correct ?

The only Rockwell software that I know to configure a devicenet is RSNetworx for devicenet. That is what I use to set up devicenet. It can read (upload) the configuration from the scanner.

You will need EDS files for the drives, on the computer that is running RSNetworx for devicenet. They can be downloaded from the rockwell site or loaded from each drive to the laptop

RSNetworx is licensed software from rockwell, so it is likely only loaded onto one or two computers at site.

Also , what is a 1770-KFD Communication Module ?

It is a serial interface used by RSLinx to connect to a Devicenet network. I've never used one, I looked it up.

What is the best way to communicate with a 1747-SDN ?

Use the method you use to communicate with the SLC 5/05. RSNetworx for devicenet will use any RSLinx communication method to communicate to the SDN through the backplane of the PLC rack - serial through the SLC 5/05, or ethernet, or controlnet if you have things set up that way. Serial through a KFD is not the most convenient way, but it should work.

A couple of suggestions from a search of Rockwell's knowledgebase are also worth mentioning:
- Increase RPI time for the drives on Devicenet. This also involves using RSNetworx for devicenet
- Use static baud rate if you use autobaud right now. This is set by a rotary switch on the 20-comm-d for each drive. I don't remember how to change the SDN from autobaud to a fixed baud rate.
- Route network cables away from AC power cables. Not easy to change.
 
Are all of the Powerflex drive in the same panel? Or are they remote? Was there any repairs or changes performed on the machine just previous to the errors? If this machine was previously running without these errors, start looking for the obvious mechanical things that could have happened to the Devicenet wiring and connections. Carefully inspect the wiring, tees, termination resistors, etc. Software does no sound like the culprit in this case.
 
Thanks for all your input. All these drives are in one panel . This machine is roughly 15 or more years old. No changes have been made to the system. No drives added , etc. I am hoping to get approval to replace with CompactLogix , with all new PowerFlex 525 drives , and HMI's at the beginning of 2018.

If you don't mind I may have more questions tomorrow .

Thanks again ,
 
No. Our electricians have been just resetting the fault. It happens about every 2 weeks. This line may be down for a change over this week , so we will have them evaluate it this week.
 
Ensure you have your terminating resistors on each end of the trunk. I've ran into issues with erratic DeviceNet faults after a running system of 7 years, and found a terminating resistor was not installed. Cleared the problem right away when I added it.
 
The fault you describe used to be quite common on Powerflex 70/700 drives with Comm20/D adapters and 15 years would put your drives into the right timeframe. The issue was with some "precision" resistors in the Comm20 adapters and the flexible PCB style connectors. The issue with the adapter must have been resolved because the failusres stopped with time and we have not seen the problem for quite a few years (and we have several hundred PF70/700's on DeviceNet).
 
Thanks. I have our upper management folks convinced to replace the SLC 500 5/05 , and replace all the PowerFlex 70's with PowerFlex 525's ( Ethernet ) early 2018. I just need to convince our corporate people to go along with it.

Andybr - What did you do to solve your problem ? I would imagine you would need to change out all your 20-COMM-D cards , for the problem to go away.

I still need to justify this project , and this information helps. I know that was many years ago. Do any of you have a link or Rockwell Recall Notice for this issue , maybe an article ?

Thanks again
 
We changed the 20-COMM-D cards on the affected drives. The fault did not happen on every drive and the issue eventually went away once we had changed all of the problem cards.
 
How many years did you have those 20-COMM-D before the issue started ?
How did you know that it was the resistors or plug ? Did Rockwell have a bulletin sent oiut ?
 
We had quite a few drives of varying ages which suffered from this problem. The feedback was from Rockwell tech. support in the UK.
One other thing which I have just remembered is that the problem cards were being identified by the drive as DPI port 1 rather than 5 and were conflicting with the HIM units. If you removed the HIM and then refitted it it would not be able to reconnect to the drive as the 20-COMM-d would take ownership of the port.
 

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