schnider- quantum plc

Hi:

We have two Redundant Quantum PLC with following arrangement:
CPS, CPU, CHS, CRS,
all of the module have the same version and are working in a dual redundant mode .

the two PLC's modbus ports are connected to a modbus device (annunciator) through 2 Phoenix Contact RS232/RS485 converter
model PSM-ME-RS232/RS485 and are working as they should in dual redundancy i.e. only the primary PLC is initiating the alarms (XXMIT block is programmed ) to the annunciator while the standby CPU has no effect on the modbus slave device .

We tried to use NOE modules in each rack of this system for a SCADA application but we noticed tht we lost the to communicate between one of the CPU's and its slave device . We swapped the NOE's and the result was the same but for one of the NOE,s which indicates tht this NOE is not suitable for the CPU of this credundant system . It is worth noting tht both NOE modules are working by means of download & upload via TCP/IP & we have download the new OS Exec Ver. 3.6 & NOE Webpages updates for both modules recently .


Pls advise us if there is anything tht we can do to correct this situation

I'm going to guess between the lines here, so feel free to ignore this if it doesn't match your real problem.

The way a Quantum Hot Standby system handles NOE modules is by assigning the configured IP address to the primary rack, and incrementing the last part of the address by one for the standby rack. These addresses switch when the primary/standby roles swap. As an example:

Primary NOE (set in the config extenstions): 192.168.0.10
Standby NOE : 192.168.0.11

You don't say what NOE versions you have, or the firmware in the rest of the system. Older firmwares (as in several years old) didn't support the NOE's in a hot standby system.

Other than that, the NOE's shouldn't be interfering with the normal Modbus port functionality at all. I've done several hot standby systems with NOE's and they work fine.

Good luck.

Oh, I know this one! I just remembered the problem I had in the spring.

There is <was> a problem with the latest NOE module's in a hot standby system. If the modules are NOT connected to the ethernet on startup everything works fine. If only one of the modules is connected it's still OK. However if the modules are both connected so that they can see each other then they refuse to go to run.

We went through this a couple of months ago. The firmware in the NOE's needed to be flashed to different version to fix the problem. The version Modicon had us go to was V 3.62 w/ Kernel 3.1. One issue we ran into - if you flash the NOE with a Unity only firmware, you'll need to have Unity to get it back to a non-Unity firmware.

Ken