CLICK PLC CPU, 4 DC in / 4 relay out, 2 channels analog in / 2 channels analog out (current / voltage selectable), requires a 24VDC power supply; 8k steps program memory, 6.4k words data memory, Relay Ladder Logic programming; built-in RS-232C programming port, additional RS-232C ASCII or Modbus RTU communications port (configurable up to 115.2 kbaud), 3-wire RS-485 networking port for ASCII or Modbus RTU communications. Real Time Clock / Calendar and battery-backed memory. Discrete Inputs: 4 DC inputs, 24VDC sink/source, 1 common. Discrete Outputs: 4 relay outputs, 6-240 VAC / 6-27 VDC Form A (SPST) relays, 1.0A/point, 1 common. Analog Inputs: 2 channels 4-20 mA or 0-5 VDC. Analog Outputs: 2 channels 4-20 mA or 0-5 VDC. Removable I/O terminal block. Battery for memory sold separately (D2-BAT-1).