View Full Version : Sercos fault and A.B.

December 13th, 2010, 09:24 AM
Has anybody delt with a Sercos ring fault that happens out of the blue? I am working with a CompactLogix L43 and three Kinetix 6000 drives. I ran my process for about 3hrs. non stop and then all of a sudden I get the Sercos fault with a code 16 #204. Two of my drives went to state 2 and the third just had the chaseing led's. I unplugged one of my fiber optic cables, plugged it back in and I am up and running again. Not real convinient to tell the customer to do. Tech support told me it could be a back plain communication problem, but no ideas to prove or fix this.

December 13th, 2010, 02:37 PM
I would check settings under module properties(connection tab). What is the RPI. What is selected for connection failure. How are you connecting devices? Any flex cards.Are you getting this error on the sercos card or on a particular drive module?

December 13th, 2010, 02:58 PM
Unfortunatly I am 400 miles from the processor right now. In offline I show no RPI value. It is not selected for major fault. The Sercos card is in the "rack" with the processor and the drives are connected with the power bus. The Sercos card doen't show any fault, but the last drive on the bus showes the code 16# 204 and trying to access it gives me drive not configured.

December 13th, 2010, 03:08 PM
I'm not sure if it affects the CPX or not. Some of the CLX processors and network cards from around late 2008-mid 2009 (not sure exactly)had a faulty backplane comms chip. There was a TSB on this. I think sercos cards were affected. The chip manufacturer was Atmel. The last two numbers on the chip were *****64. The chips with *****65 at the end and other brands were Ok. If you have a card with this chip, AB will replace it for free. These chips caused some weird intermittent comms issues. I battled one for months on a nearly new machine communicating to a C# app. One tech support guy finally thought to check it. Good Luck!

December 13th, 2010, 03:12 PM
Settings sound correct. Drive not configured would be normal during a connection fault. Has anyone swapped the drive and or back plane with a spare to test?

December 13th, 2010, 03:38 PM
How would I check the chip number? Is it part of the serial number on the Sercos card?

I didn't really have the option of trying to swap out anything because we were in the customers plant Friday when this reared its head and our distributer was 400 miles away.

December 13th, 2010, 03:44 PM
Once again, I'm really not sure about the CPX stuff. On CLX, there is a chip on the pcb in each card that is almost a 1" square. You can read this info directly off of that chip.

December 13th, 2010, 03:48 PM
I wonder if AB is saying if its one slot of the back plane of the entire chassis. If just one slot are there any spare/empty slots?

December 13th, 2010, 03:59 PM
A backplane comms fault on compactlogix means a bad card. There is no backplane in the sense that we are all used to. They comm card to card via ribbon cables. From what I have seen (only on IO cards), when one card is having comms issues, every card after it in the "chassis" will fault and appear to have comms issues also. All of my experience with the cpx has been on the 1769 bus. I believe that the L4x and motion card comm on the 1768 bus.

December 13th, 2010, 04:10 PM
No empties. They had me check the connecting pins to make sure they were not bent, but I don't see how that could be the case when it runs for hours. It also confuses me why unplugging one of the fiber optic cables and re connecting it cycles everything back to level 4. I would think if it was a back plane issue I would have to cycle power.

December 13th, 2010, 04:14 PM
The back plane they were talking about is the power rail to the Kinetix drives. They said the main drive commuicates to the other two drives through it.

December 14th, 2010, 12:39 AM
We had an issue on one of our Munchskin lines similar to that and what we found was a ground issue one of the cables shielding wasn't properly attached. Might sound stupid but thats what the equipment rep said he found when he came out to work on it.

December 14th, 2010, 06:59 AM
Got bit by the grounding bug before, so cables are good but I didn't check the main ground to the panel.

June 12th, 2017, 02:23 PM
Did you found out your issue? I'm having a similar problem on some of my machines. Got a rack with 2 PLC and 4 sercos (M08se) card. Red light on ''OK'' from time to time on a sercos card at the time ( 16#0204 when looking online). The dates don't match the technote (too old). We upgraded the firmware on the PLC and sercos about 3 years ago and think it might be related, but two other machine (more recent) runs the same firmware without issues... Chip is an ARM ending with 64, new machine is ARM ending with 65...