G
I am having a problem replacing a 6ES5 318-8MB12 in an MCC. The module is 16+ years and is becoming susceptible to heat. When it gets “heat stress” it flashes a bus fault intermittently. This is attached to a S7 414-2 CPU. We have 13 drops on this Profibus network. I have replaced these modules in the past without issue. New modules are 6ES5 318-8MB13. This particular drop will not accept the new module.
I tried replacing the original 6ES5 318-8MB12 interface module with a new 6ES5 318-8MB13. I could not get it to work. I had the address dip switches set correctly and the switch 8 (DP-norm) set correctly. The PLC recognized the new module, there were no buss faults, but it would not see the attached I/O. We get process image update errors for the I/O attached to this new module.
Yesterday we had a maintenance down day and I did some experimenting to try to resolve the issue. I tried another new 8MB13 and got the same results, could not update the process I/O image. I tried replacing another old 8MB12 in an operator station with one of the new 8MB13’s. This worked fine with no problems, as I would have expected. I then took the old 8MB12 that I had just removed from the operator station and tried it in the MCC. I got a bus fault with the used 8MB12. I tried replacing the first module back plane that connects to the 8MB12/13 and that didn’t help either. I’ve also checked the power supply and am getting a steady 24.1VDC.
There are 7 input cards and 7 relay output cards in this rack. I changed the HW configuration to only inputs, removed all the output cards, and the 8MB13 is happy. If I add any of the output cards, I am back to process image update errors. I have a lot of spare I/O on hand, so I replaced all the cards with new and still get the same result. So far I have tried three 8MB13’s, all new I/O cards, and even new terminal modules.
So as I type this we have the original 8MB12 installed as it’s the only one that works (unreliably).
The only new thing I can think of trying is to upgrade this rack to a newer style. I don’t have a lot of experience with the newer stuff. I do know the ET200B is junk. I could use ET200M, but the all the wiring would have to be replaced as it is so different than the ET200U. We cannot have this system down for more than a few hours every other week, so it’s frustrating to work on, and the time to re-wire is important.
Does anyone have a suggestion of an ET200 type that would be wiring compatible with the old ET200U? And is it as reliable as the old ET200U? I’ve had the old ET200U racks completely encapsulated in ice and so hot that the wring duct melted onto them and they just work.
I tried replacing the original 6ES5 318-8MB12 interface module with a new 6ES5 318-8MB13. I could not get it to work. I had the address dip switches set correctly and the switch 8 (DP-norm) set correctly. The PLC recognized the new module, there were no buss faults, but it would not see the attached I/O. We get process image update errors for the I/O attached to this new module.
Yesterday we had a maintenance down day and I did some experimenting to try to resolve the issue. I tried another new 8MB13 and got the same results, could not update the process I/O image. I tried replacing another old 8MB12 in an operator station with one of the new 8MB13’s. This worked fine with no problems, as I would have expected. I then took the old 8MB12 that I had just removed from the operator station and tried it in the MCC. I got a bus fault with the used 8MB12. I tried replacing the first module back plane that connects to the 8MB12/13 and that didn’t help either. I’ve also checked the power supply and am getting a steady 24.1VDC.
There are 7 input cards and 7 relay output cards in this rack. I changed the HW configuration to only inputs, removed all the output cards, and the 8MB13 is happy. If I add any of the output cards, I am back to process image update errors. I have a lot of spare I/O on hand, so I replaced all the cards with new and still get the same result. So far I have tried three 8MB13’s, all new I/O cards, and even new terminal modules.
So as I type this we have the original 8MB12 installed as it’s the only one that works (unreliably).
The only new thing I can think of trying is to upgrade this rack to a newer style. I don’t have a lot of experience with the newer stuff. I do know the ET200B is junk. I could use ET200M, but the all the wiring would have to be replaced as it is so different than the ET200U. We cannot have this system down for more than a few hours every other week, so it’s frustrating to work on, and the time to re-wire is important.
Does anyone have a suggestion of an ET200 type that would be wiring compatible with the old ET200U? And is it as reliable as the old ET200U? I’ve had the old ET200U racks completely encapsulated in ice and so hot that the wring duct melted onto them and they just work.
