Module overview and key ratings
The Siemens 6ES7422-5EH00-0AB0 is a 16-channel digital output module for the S7-400 programmable logic controller. Each output is rated for 2 A continuous at 120 V AC, with a permissible supply range of 20 V to 132 V AC. That 2 A per channel is the maximum continuous current — the real-world limit depends on ambient temperature and whether a fan assembly is fitted. At 40 °C the module can deliver 16 A total (24 A with fan); at 60 °C that drops to 7 A (16 A with fan). For a conveyor zone with multiple solenoid valves or motor starters, you need to sum the loads and check the derating curve, not just the per-channel number.
Switching performance and protection
Switching speed is modest — 10 Hz maximum with resistive load, 1 Hz on lamp load — so this module is suited for on/off control of contactors, relays, and indicator lamps, not for high-speed pulse trains. The response time is 33 ms max. Each output is individually short-circuit protected by a replaceable 8 A, 125 V fuse (2 AG form factor), and a spare fuse is included on the module. There is no zero-crossing switch, so inductive loads will see full switching transients; plan for appropriate snubber or flyback suppression at the load.
Diagnostics and integration
Diagnostics are parameterizable — the module can report internal faults (INTF, red LED) and external faults (EXTF, red LED) to the CPU. Diagnostic information is readable over the backplane bus, which helps an integrator pinpoint a blown fuse or a shorted output without climbing into the panel. The module draws 600 mA from the 5 V DC backplane bus, so check the S7-400 power supply budget before adding it to a rack. Galvanic isolation is tested at 1500 V DC between channels and the backplane bus, and between channel groups (groups of 1).