SLC 5/04 dropping off line

While researching this new problem, I thought I would ask here since this is better than any knowledgebase.

I have a system that has 2 SLC 5/04 on DH+ at 56K (nodes 1 and 2). There is a message (MSG) from the processor on node 2 to node 1 that send 1 word. This is connected to a DH+ card in a contrologix gateway that is connected to our computer thru an ethernet card that gathers some information from both processors. System has been in place and working for 10 years.

I got a call from my tech on the floor saying that when he went to connect to the processor, he got an error saying target device is not a slc processor. I opened my RSLinx (2.50) and saw the processor dropping offline every 5 seconds then coming right back. Last time I saw this it was the terminating resistor (it is at the end of the line). Changed the resistor and no difference. Ran a new blue hose on the floor and still the same problem. Put the old system back in service and decided to research this a little.

Anyone experience this before? I will post more as I try to fix this.

Problem solved

I hate to answer my own post (it's like talking to yourself) but I did get this fixed.

I found the MSG instruction had an error in it (but no error bit set) that was code 37. Answer ID 18352 gave a long list of things to check for - most of which I already checked or eliminated.

The one that fixed it was the FRN of the processor. I was running FRN 3 and the tech note said I needed to be above 5. Since I did not have a flash upgrade, I just installed a new processor with FRN 7.

This has fixed all the problems.

I have over 8 of these little networks (similarly wired but not exact) all running the same FRN on the SLC 5/04. After looking at them, I did find one that was exhibiting the same symptoms but not causing any problems right now. I will try to get a flash upgrade and verify that fixes the problem and it wasn't just a bad processor ( you never know, it could have lost a couple of bits ).

brucechase said:

I hate to answer my own post (it's like talking to yourself) but I did get this fixed.

Click to expand...

I thought all programmers talked to themselves. I do, its the answering part that bothers me.

Sometime the on;y to get answers that make sense is to talk to yourself. And all programmers do talk to themselves

brucechase said:

While researching this new problem, I thought I would ask here since this is better than any knowledgebase.

I have a system that has 2 SLC 5/04 on DH+ at 56K (nodes 1 and 2). There is a message (MSG) from the processor on node 2 to node 1 that send 1 word. This is connected to a DH+ card in a contrologix gateway that is connected to our computer thru an ethernet card that gathers some information from both processors. System has been in place and working for 10 years.

I got a call from my tech on the floor saying that when he went to connect to the processor, he got an error saying target device is not a slc processor. I opened my RSLinx (2.50) and saw the processor dropping offline every 5 seconds then coming right back. Last time I saw this it was the terminating resistor (it is at the end of the line). Changed the resistor and no difference. Ran a new blue hose on the floor and still the same problem. Put the old system back in service and decided to research this a little.

Anyone experience this before? I will post more as I try to fix this.

Click to expand...

You mean at each end of the line right?

allscott said:

You mean at each end of the line right?

Click to expand...

No, I mean the last time I saw a processor dropping offline and coming back repeatly, it was the last processor in the line and the resistor was not installed. It only affected the last processor on a data highway system with 7 total nodes.
The other end had the resistor and no other unit was exhibiting problems.

Just to be clear, you have two resistors, one on each end correct?

allscott said:

Just to be clear, you have two resistors, one on each end correct?

Click to expand...

Yes, a resistor at each end.