Eight relay outputs with built-in snubber
The 6ES7322-1HF20-0AA0 is an SM 322 digital output module for the SIMATIC S7-300 rack, delivering eight relay outputs rated 5 A each at 24 V DC or 120–230 V AC. The integrated snubber across each relay coil suppresses inductive kickback from contactors, solenoids, and motor starters — so out here in the grease, a valve or a conveyor contactor won't weld the relay contacts on the first open. The 40-pin front connector carries the field wiring; the backplane bus provides the 24 V DC module supply and the PII data.
What the specs mean for your panel
Eight relay outputs means eight independent Form C (SPDT) contacts, each rated 5 A — enough for a small contactor coil or a solenoid valve directly, no interposing relay needed. The 24 V DC side powers the module logic; the 120–230 V AC side is the switched load. Optically isolated between the backplane and the field, so a short on the load side won't take out the S7-300 backplane bus. The 40-pin connector is the standard S7-300 front connector; the module snaps into any S7-300 rack slot.