PLC Simatic S7-221 Dimensions W x H x D: 90 x 80 x 62 mm Inputs: 6 Digital, 1 Analogue (Potentiometer 8 Bit), 4 High Speed Counter Inputs, abbreviated: 6 DI, 1 AI (Potentiometer 8 Bit), 4 HS Operating temperature: 0...+55 °C Outputs: 4 Relay, 2 Impulse Outputs, abbreviated: 4 RO Analogue inputs: Potentiometer 8 Bit Communications interface: 1 x RS 485 Data buffer: typ. 50 h Data memory: 2 kByte Inputs/outputs, max.: - Operating voltage: 115/230 VAC Processing time per binary statement: 0.22 μs Real-time clock: optional Series: SIMATIC S7-200 Protection rating: IP20 No. of analogue inputs: 1 No. of digital inputs: 6 No. of high speed counter: 4 No. of impulse outputs: 2 No. of relay outputs: 4