ABB Procontrol P13 panel bus traffic director alarm blinks for a second, then processor alarm blinks a sec and becomes normal. as a result entire plant trips. any idea?
Alarm LED on traffic director most likely indicates failure of this card. As traffic director manages the entire local bus (one or more P13 racks) all other cards including processor are also affected. Put it this way - processor reads data from the local bus, and if the card managing this bus fails, this data becomes not available by processor (hence the alarm on processor) - which is critical failure and can easily trip the plant. Most likely failure of traffic director causes immediate alarm on the processor.
