8 digital inputs for the S7-200 SMART backplane
The Siemens 6ES7288-2DE08-0AA0 is a digital input module for the SIMATIC S7-200 SMART PLC family, providing 8 inputs that accept 24 V DC sink or source field wiring. Signal thresholds are defined: a logic 0 is below 5 V DC, and a logic 1 spans +15 to +30 V DC, with a typical input current of 4 mA per channel at 24 V. The module draws a typical power loss of 1.5 W from the backplane. Response time is symmetrical at 200 µs for both off-to-on and on-to-off transitions, suitable for fast discrete sensing on a conveyor or packaging line. Inputs can be wired in groups of two, and parallel switching of inputs is permitted — useful for paralleling contacts from multiple sensors into one channel.
Panel fit and wiring constraints
The IP20 rating means it belongs inside an enclosure, not on the open line side. Unshielded sensor cable runs are limited to 300 m; shielded runs can extend to 500 m. Supply tolerance is 20.4 to 28.8 V DC, so a regulated 24 V supply is recommended.