SM811 SYNC LED is turned off in Live ESD System (PM865).
ESD PLCs PM865 are running in redundant mode with redundant SM811 modules. Both controllers redundancy (DUAL) light is ON and CPU A is Primary. Primary CPU A is active at the moment and SM811 SYNC light is ON. but standby SM811 module SYNC light is OFF. I need support or guidelines how to resolve this issue on live ESD systems. Entire plant is running on same PLCs.
I need support for below points;
Question 1: How to enable standby SM811 SYNC light ON in live System (without shutdown)?
Question 2: With Standby SM811 SYNC LED OFF, If swithover is performed from CPU A to CPU B, would it successfully transfer control to CPU B without going in FAULT.
Looking forward valueable support in order to resolve this issue.
Voted best answer
There is a bit of difference in configuration of SM810 and SM811 in redundancy. Physically, the instatllation and connection will be same. But there is one difference every new user forget to address which we should do according to safety manual.
1. In SM810, the I3 input is not used. Whereas this is one of the most important thing to address. This I3 is used for Hot Insert, i.e. we need a clock pulse input on this channel to avail the redundancy of SM811. You can do one thing: Connect both the I3 of the SM811s into a 24V supply via a switch and give a pulse input to it which will make the Sync LED on SM811 to lit continuously (instead of blinking). Follow the screenshot.
2. When your standby LED is not lit (i.e. SM811 not in Sync), only SM811 redundancy is not there. whereas you still have CPU (PM865) redundancy. So switchover of CPU will still work, however when there is fault triggered in Primary SM811 then it would shutdown your entire system.
Hope it works.