Output Ratings and Load Handling
The 6ES7322-1HF10-0AA0: This SM322 module provides 8 relay outputs, each rated for 8 A with resistive loads at both 230 V DC and 120 V AC, and 5 A continuous per channel at up to 60 °C. For inductive loads, the rating drops to 3 A at 230 V DC and 2 A at 24 V AC — a key derating to account for when switching solenoids, contactors, or motor starters. The relay contacts are rated for 300,000 mechanical cycles at low load, but this drops to 100,000 cycles at 230 V AC, 3 A. That mechanical endurance figure sets the service life in high-cycle applications like pick-and-place or packaging lines. Short-circuit protection is not built in and must be provided externally — a per-channel fuse or circuit breaker is required in the field wiring, which is standard practice for relay output modules in a control panel.
Integration with S7-300
The module fits a standard S7-300 DIN rail slot with a 40 mm width and 125 mm height, requiring a 40-pin front connector for field wiring. It draws a maximum of 40 mA from the 5 V DC backplane bus and 125 mA from the 24 V DC load supply L+. Unshielded cable runs up to 600 m are supported for the digital outputs, and shielded runs up to 1,000 m. The module does not include diagnostic alarms, wire-break detection, or fuse monitoring — so fault finding relies on the external protection and PLC logic.