Controller Input Voltage 12 to 24V Output Type Analog Relay 2 A Amps 1 LAN expansion bus 1 RS485 - screw terminal block Modbus serial link Slots Timers Programmable LED Display Port Type 1 LAN Expansion Bus 1 RS485 contacts usage Volt-free contacts Discount Schedule PC12 Modbus Modicon M171 Optimized Flush mounting 22 I/Os product specific application HVAC and pumping solution Depth 2.43 in Height 4.33 in Width 5.51 in