Mitsubishi PLC Plug-in Relays

[Guest bahart]

My facility uses many of the following Mitsubishi PLC's: AJ65BTB2-16R CC-Link I/O, 16 Relay Out. We are seeing failures of the relays internal to the PLC. These failures are due to the relay reacing end of life cycles. These relays are soldered to the board. Does anyone know if this PLC is available with plug-in relays, or if there is a compatible device with plug-in modules. Replacing a $350 PLC because a $2 relay failed does not make sense to me.

[Crossbow 294]

What you've got there is not a PLC, but a remote terminal block for CC-Link. One option is always to switch to transistor outputs and drive an external relay. Otherwise, I do not know of a relay module with socketed relays in that family.

[panic mode 246]

can you tell us what is the load, voltage and current you are switching? how oft do they switch? do you have suppressors? how many cycles it runs until it dies (an estimate would be ok). i have seen quite few modules with relay outputs that toggle every second 24/7 for years without failure. maybe there is something to be done with the design of those circuits. what relay is inside? $350 is a bit of a steep price. try changing supplier and meanwhile buy soldering iron and vacuum pump (each ca $5-10). you know this could be job security