TheWanderingMerc
Member
Hello All,
I'm currently having issues getting a backup rack for a Modicon Premium TSX H5744M to function properly when it is brought online. Only one rack has power at one period of time (Apparently the system was using the other rack as a hot standby at one point but was changed to just have one powered due to issues years before I began to troubleshoot.) Whenever my customer wishes to switch PLCs, which they do every fall and spring, they turn a breaker off for the active PLC and turn the breaker on for the other. Both PLCs are to be setup identically with the same program. Now this method has worked flawlessly up until this past switchover when switching from Rack 1 to Rack 2. Rack 2's 1st modbus card fails to start scanning and the customer reports that several of their sensors are reading incorrectly(note these sensors aren't coming over modbus at all). I've tried redownloading the program to the Rack 2 PLC and restoring a freshly exported data file from Rack 1 (Rack 1 works flawlessly) and the problem persists. Weirder yet is that when I turn the PLC from Run to Stop and back to Run mode the first modbus card begins to work. It should be noted that there are no faults and no warning lights on the processor, also I checked the battery voltage and it was 3.6VDC as specified. As far as I'm aware the PLCs in Rack 1 and Rack 2 are identical!
I will openly admit I am a Rockwell Programmer through and through and SE products aren't my forte, am I missing a step or is there something else that could be wrong?
Thanks in advance for the help!
I'm currently having issues getting a backup rack for a Modicon Premium TSX H5744M to function properly when it is brought online. Only one rack has power at one period of time (Apparently the system was using the other rack as a hot standby at one point but was changed to just have one powered due to issues years before I began to troubleshoot.) Whenever my customer wishes to switch PLCs, which they do every fall and spring, they turn a breaker off for the active PLC and turn the breaker on for the other. Both PLCs are to be setup identically with the same program. Now this method has worked flawlessly up until this past switchover when switching from Rack 1 to Rack 2. Rack 2's 1st modbus card fails to start scanning and the customer reports that several of their sensors are reading incorrectly(note these sensors aren't coming over modbus at all). I've tried redownloading the program to the Rack 2 PLC and restoring a freshly exported data file from Rack 1 (Rack 1 works flawlessly) and the problem persists. Weirder yet is that when I turn the PLC from Run to Stop and back to Run mode the first modbus card begins to work. It should be noted that there are no faults and no warning lights on the processor, also I checked the battery voltage and it was 3.6VDC as specified. As far as I'm aware the PLCs in Rack 1 and Rack 2 are identical!
I will openly admit I am a Rockwell Programmer through and through and SE products aren't my forte, am I missing a step or is there something else that could be wrong?
Thanks in advance for the help!