In our machine the central processor is an S7-416, we have 1 Profnet network attached to the Profinet IO Port of our central CPU, there are several IM151-3PN HF (6ES7151-3BA23-0AB0), attached to the profinet network, in one of this IM's (device number in the profinet network is 1, the IP addres asignet to this IM is 172.16.184.30, and device name is MH-HK1) the following condition has been detected several times in the last days:

1. All the IO cards and PM's that are attached to this IM shows SF LED on.

2. IM does not show any SF LED ON, nor BF LED ON or Flashing, PWR LED is lit, also PRT2 LED is on (Our profinet cable is plugged in port 2).

3. By checking HW status online, we do not see any IM or IO module faulty.

4. By checking diagnostics buffer in the CPU, there is not any register of a fault event related to this specific IM.

5. CPU does not go to Stop due to this event. The machine stops because it miss some IO's, that when missing trigger fault events in the program.

6. The SF LED ON status remains until power is cycled to the whole IM.

7. By cycling the power to the IM, SF LED's get to OFF, and CPU goes to stop Mode.

8. We trigger a Warm restart, reset all faults and start running again.

Based on this breif description would you please help us to:

a. Suggest a root cause for this behaviour.

b. Suggest some corrective actions to prevent this (Change IM, clean and review backplane connections).

c. Do you have heard about simillar problem?

d. Any other advice or suggestion you may like to shere with us?

I'm attaching a PDF doc which contains images of the HW online status at the moment the fault was present.

Thanks a lot for your help Have great evening/day.

Hi,

this is a strange behaviour. I saw firmware of IM151-3 is up to date. What about the PLC-Firmware, can you update?

Regards,

Towome

Hello,

Replace the IM module with another existing one which doesn't have that behaviour.

It is really strange that software doesn't detect wrong.

From my experience there should be a problem with power supply. But this will affect also the profibus communication.

I have almost the same behaviour with CPU416 and ET200S (IM151-1). But always when have problem with the power supply. 

Best regards,

Hristo Mihalev

Dear Towome & Umencho,

First let me thankyou for your valuable help, insecond place:

I forgot to mention that we have an identical IM with the same IO/HW configuration running in the machine, the instalation is the same, that IM has not showed this fault.

The conficltive IM is mounted in a robot, the power supply wiring for the IM pass trought the robot structure, and moves along with it as well than profinet cable, so it is very plausible that ppower supply wiring is damged, but if so, i will expect to observe some error in the PLC. Any way if the PLC do not report the error or not, we will check/replace that wiring. Then our next move will be maybe change the IM.

Dear Umencho, would you please share what was wrong in your Power supply? (Grounding PS deffective or wiring maybe?).

Dear Towome, iwill check also FW version of both CPU and IM, but change FW will be my last resourse in this case ;)

Once Again, thanks a lot for your help.

Good Day. 

TEBANCH

I forgot to mention that we have an identical IM with the same IO/HW configuration running in the machine, the instalation is the same, that IM has not showed this fault.

 hi TEBANCH,

IP and Devicename of the two Stations are unique, are they?

I suppose you copied the already existing station in HW-config. Try to config it new, manually.

hope this helps,

regards, 

mopS04

 

TEBANCH

I forgot to mention that we have an identical IM with the same IO/HW configuration running in the machine, the instalation is the same, that IM has not showed this fault.

 hi TEBANCH,

IP and Devicename of the two Stations are unique, are they?

I suppose you copied the already existing station in HW-config. Try to config it new, manually.

hope this helps,

regards, 

 Hello, thanks a lot for the suggestion, just to clarify, yes the IP, device name and device number are unique. I'm not comissioning or starting up the system, this system has been running for about 8 months, so there (i think) is no need to change WH config, i dont think this is a HW configuration issue.

I did check wiring and robot harneess,  this fault has not appeared since the wiring inspection was done, but i have to wait some time and keep tracking this problem. I will update if there is any new.

Have a great weekend. 

Dear Colleagues.

Here an update on this issue.

After power supply wiring chekup, what we found was that there was some fittings a little bit loose, also we re-tight some terminals and multipoint connectors, we did check grounding as well but did not find anything strange, no other corrective action other than re-tight was done.

So far the problem has not appeared again, i have created a support request to find out why, when the fault was active, the CPU did not repport the error in the Diagnostics Buffer. So far the tech support point to the CPU FW version as the "root cause" for such behaviour, the actual FW is V 6.0.3 (please check attached image).

Well thats it for now, i will update information if there is any important change in the next days, Houpfully this may help others with simillar issues.

Have a great day .

Hello,

I will like to inform you that the final solution to this problem was not the described before.

A few days after we implemented the actions mentioned in the previus post, the fault/problem appeared again, and the final solution for this was:

 Disasemble all "backplane" connecctors (one by one), clean them with compresed air and cleaning products for electronics, and reasemble the whole rack.

No components or cards were changed, we have been "clear of faults" since this actions were done.

I'm still angry (it's a way to say it  ), about the fact that the PLC does not report this status neither in the online HW diagnostics or Diagnostics Buffer on the CPU.

I hope this may help someone else.

Regards.

Hello dear colleagues.

For my bad luck, the problem described in the previus posts has appeared again in the past days, so that makes me belive that our real problem is that the ET200S backplane is getting loose due to exesive vibration caused by the robot motion as well as the vibration generated by the hidraulic system that is mounted in the robot.

So supposing that my theory is right, may you please suggest anything i may try in my system to avoid this? (Maybe to use SiPlus modules instead of standard ones, or add rubber pads at the sides of the rack?).

Well, in the other hand this fault has created some other problems in the CPU, please let me explain further:

The conflictive IO Rack contains some fast Analog IO cards and fast counters, this IO's are being updated in OB38 (1 ms interrupt), so when the fault happens sometimes PLC goes to Stop (all OB's to avoid CPU stop by HW faults has been loaded) due to program time excecution overflow (some times PLC does not stop). (Just for the record, we suspect that due to this problem as well than a bad designg in the machine safeti we did have a machine crash 2 days ago.)

It is ok for me if PLC goes to Stop under this conditions, my real problem whith this is that it's been 2 times now that the CPU has lost the programm!, i mean the firts time that ET200S rack started to fail, the CPU memory was cleared by itself! (in that time i blamed a colleague for it ). But now i have seen it with my oun eyes.

What happens is the following:

ET200S starts to fail continually (some times causing PLC stop), in some point after some ET200S faults PLC goes to Stop, then i try to go online and pass it to Run Mode, but PLC does not switch, then i try to check HW to see if some slaves are missing, but when i try to see HW online, the HW editor indicates a configuration mismatch, then i go upstairs to see the CPU and i find it with all LEDS blinking (which indicates a memory reset request right?), then i turn off CPU Power suply (Bateries are good both), then i turned ON PS, and i try to chek Online blocks, and CPU is empty! .

Ok CPU is emtpty , i download my BKP and last version of online DB's, machinne is rruning again but, do you see any relation between ET200S consecutive faults and the CPU fault? Can the ET200S fault cause a disturb in the CPU memory so it will ask for a reset?

I will apreciate any help, or suggestions you may provide; thanks a lot for your help.