Eight AC inputs with per-group isolation
The 6ES7221-1EF22-0XA0 is a SIMATIC S7-200 EM 221 expansion module packing eight digital inputs rated for 220/230 V AC (47–63 Hz). Each input is isolated by optocoupler, and the channels are grouped into eight separate isolation groups — one per channel — so a fault on one input won't drag down its neighbor. Signal thresholds are set for AC line levels: a logic "0" sits at up to 20 V AC, and a logic "1" kicks in at 79 V AC or more with a typical draw of 2.5 mA per input. The transition time from 0 to 1 maxes out at 15 ms, which matters if you're counting fast pulses off a proximity switch.
Cable runs and power budget
Maximum cable length to the field device is 500 m shielded, 300 m unshielded — plenty for running sensor wires across a plant floor or down a conveyor line. The module draws 30 mA from the 5 V DC backplane bus and dissipates 3 W typical, so budget that into your S7-200 power supply calculation.
Active lifecycle and sourcing
Sourced through independent distribution channels and quoted to order against your BOM quantity.