The PLC-K523 Discrete Input and Output Expansion Modules are offered in Transistor or Relay outputs and sinking or sourcing inputs. These units come with 4 inputs and 4 outputs or 8 inputs and 8 outputs. These units are ideal to expand beyond the onboard inputs and outputs of the PLC-K5 CPUs, which can handle up to 136 I/O points with a maximum of 6 expansion modules. The inputs are rated for 3.5mA and can be configured for either sourcing or sinking. The transistor outputs are rated for 500mA @ 24VDC and come only in a sourcing configuration. The relay outputs are rated for 2A @ 30VDC or 250VAC, and are great for switching on and off high load devices AC or DC devices, particularly AC or DC motors. The transistor output modules are opto-isolated for unit protection.