FEC12
We have installed new redundant BRC410 at existing PCU, We are using 2 FEC12 with 75FT NKTU01 cables. Data of these modules is showing in Composer and HMI but after some time, there is bad values at all channel, we observer that Modules Power lights (green) goes OFF and then again light ON after few moments.
Light blinking speed is not fix, it blink after few minutes and some time 2-3 times in a minute.
We installed this modules with other FEC 12 location (Same PCU but different BRC), there is stable values.
We replaced this module with already tested module, We observe same behaviour means light blinks.
Othere Digital modules (in same BRC and MMU) are stable.
Kindly support to resolve problem.
Answers
Hi,
You have done most of the work in determining that the fault appears to be related to location in the rack rather than the slave module itself.
The FEC green status LED cycling from green to off is often a sign of corruption on the expander bus. This can be caused by a faulty module (controller or slave), faulty or incorrectly set slave address dipswitches, expander bus configuration or even the MMU backplane.
The FEC will blink periodically to indicate a hardware failure but as you mentioned the blink rate is variable and the fault does not stay with the module this is not the case.
The digital IO modules may not show the same problem as they may not have a status LED as such. The FEC, ASO, CIS and DSO15 have status LEDs from memory but the DSI family and DSO14s do not.
The slave indicating the problem is often not the faulty module but is being affected by another module misbehaving.
You could also try pulling out all of the slaves and installing them incrementally until the problem returns.
Is the redundant pair of BRC410s working correctly? You could try running on one BRC410 controller at a time to rule out a BRC410 redundancy problem or faulty expander bus transceiver. Alternatively, try another controller altogether.
Is the new BRC410 is connected to an expander bus that is isolated from all other controllers, NPMs, ICIs etc.
There is a limit to the number of some of the "old" N90 slaves that can be added to an expander bus(NDSM03, DSM04,DSM05,CIS01). The modules have a expander bus transceiver that places a higher load on the bus than current salve modules. The BRC300/400/410 are less tolerant of these modules than the older controllers. Refer WE-DOC-3BUA00099A-1-A for more details.
You could also try disconnecting the NKTU01 cables to rule out any field problems.
Good luck,
Alan
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