The 6ES7321-7EH00-0AB0: Key differentiator: per-channel wire-break detection triggers when the sensor current drops below 1 mA. That’s a rare feature on a S7-300 input module — saves hours of chasing intermittent faults on a 2-wire prox or limit switch. Input filter is parameterizable in five steps from 0.1 ms to 20 ms, giving flexibility between noise immunity and scan-rate. Diagnostic alarm and hardware interrupt are also configurable, so you can map faults directly into the CPU OB.
Integration Notes
Single-width S7-300 module: 40 mm wide, 125 mm tall, 120 mm deep. Mounts on any S7-300 rail. Requires a 40-pin front connector (sold separately). Backplane draw is 90 mA at 5 V DC — verify CPU power budget. Inputs isolated from backplane via optocouplers tested to 3 500 V DC; no channel-to-channel isolation — all 16 share a common group. Wire unshielded sensors up to 600 m, shielded up to 1 000 m. Supports 2-wire sensors with a permissible quiescent current up to 1 mA. For signal '1' the typical draw is 3.5 mA at 24 V. The nominal 24 V DC supply can range from 24 V to 125 V DC with reverse polarity protection.