1794-L34 replacement

[chelton 66]

I have a couple of 1794's still operating on different sites. They all have 1788-enbt/a's for comms with scada/hmi. What would be the best migration path and spares to keep? Thanks

[PLCMentor.com 60]

Well since nobody else has taken a stab at this I will - with a qualification that I have not used the flex logix plcs; however, I do use a fair amount of flex I/O. My assumption here is that you are also using primarily flex i/o with this system. With that said, I would think it would be relatively painless to add and AENT and convert your I/O to remote I/O on either a compact logix platform or control logix platform. You could go with one of the other networks, but I have found Ethernet I/P to be a solid communication medium and easy to setup and troubleshoot.

[chelton 66]

PLCMentor Thankyou for the reply, Yes the systems are primarily flex i/o, i have plently of spares for the i/o modules, but do not have a spare processor that i could use to get the plants running again if needed. If using the aent and ethernet/ip, is ok to have scada comms using the same module or is it recommended to have separate networks? I think a control logix would be an overkill, the systems have only 6 digital i/o 2 analogue i/o with only small programs <600 rungs of ladder.

[dmargineau 6]

I would consider migrating your application to the CompactLogix 1769-Lx platform (http://ab.rockwellautomation.com/Programmable-Controllers/CompactLogix-Controllers#/tab5) The 1769-Lx platform could be scaled "up" or "down" depending of the user's requirements and provides almost the same functionality as its larger "cousin" the CLX. You could replace the FlexLogix processors with 1794-AENT EtherNet/IP communications modules networked within the CompactLogix EtherNet/IP port(s) circuitry and continue controlling the exising I/O as EtherNet/IP remote racks.