Hi,
either one of us or you needs to read the datasheets ... I think it makes sense that you read it ;-)
It shouldn´t be that difficult to find out input voltages and input currents.
Sadly you don´t give the information if a PLC_HIGH should generate a Mitsubishi_HIGH or ..-LOW.
Thus I tell the simple - inverting solution: HIGH --> LOW
PLC_out -- 10k -- BJT1_base
BJT1_base -- 1k -- GND
BJT1_emitter -- GND
BJT1_collector -- Mitsubishi_in
In case the the Mitsubishi_input has no internal pullup --> you need an external pullup resistor:
24V -- R_PU -- Mitsubishi_in
BJT1 is a standard NPN transistor. In detail it depends on the (missing) voltage and currents. Try BC547
R_PU value depends on Mitsubishi input voltages and currents. Try 10k, maybe you need a lower value.
Klaus