Infi90/Harmony PCU Communication Loss
I'm wondering if anyone can help me out with an issue I am experiencing. We are having an intermittent comm loss to all controllers in a PCU cabinet. The PCU has an MPSII with 4xIEPAS02 modules, redundant NIS/NPM modules and a variety of controllers (MFP02's). In 800xA we are seeing that the nodes are going offline for a split second and coming right back with nothing redlighting. The NIS/NPM's show no errors. Could this be a symptom of a failing IEPAS02? We have tried failing over to the redundant NIS/NPM pair and the problem persists. The voltages are ok when the problem isn't there, so we are thinking either a failing IEPAS02 or some kind of connection. The IEPEP02 is not failing over to the secondary power source according to the power quality logger we have on power input #1. I don't know if the alarm is coming from the Bus Monitor card, but we will try to log the 5V, 24V, 15V and -15V.
We have been checking the node status with the Harmony Control Equipment aspect in 800xA, the but i don't know if the errors in there latch or if it just gives you a current snapshot. I was kind of hoping we could use the "Node Environment Status" from the NPM aspect, but it shows as good.
I'm getting a support case in to ABB, so if nothing else maybe this can help someone in the future.
From what you are saying, it appears that you have MPS I, which used the IEPAS0x modules and IEPEP0x series power entry panels.
I did see an issue similar to what you are describing, although I am not able to say for certain that your issue is caused by the exact same problem. The issue was a power related problem but it was not the power system but rather the power feed itself. In this case, the customer had the PCU cabinet being directly fed rather than going through a UPS or some type of power signal conditioner and what we were seeing was intermittent dips in the power feed to the cabinet. As the power would dip, the DC output from the supplies were seen to also dip.
Now this was momentaneous and the voltage to specific modules would only dip below the minimum operating voltage of these modules (you can find this value in the spec section of the manual). As each module has a slgihtly different drop out voltage level this would not hit all modules. When this was seen, it would cause these modules to reset and thus if the NPM or controller would drop out, it would take some seconds before it restet and came back online.
So, I suggest that you check you power feeds and make sure that they are conditioned and regulated to ensure a smooth power feed.
I would also go through and check the voltage levels at the Bus monitor module and if they are close to the minimum acceptable level as stated in the manual you may also want to consider cleaning the contacts on the power module tips and the point of contact in the MMU. I have seen issues where dirty contact points can reduce the voltgae seen by the modules, cleaning these things should help.