Overview
The 6ES7422-1FH00-0AA0 is a Siemens SM 422 digital output module for the S7-400 system, providing 16 outputs rated at 2 A per channel for 120/230 V AC loads. It draws 16 W from the backplane and occupies a 25 mm wide slot in the rack.
Function & operation
The module includes a built-in 8 A, 250 V quick-response fuse per output group; a blown fuse triggers the red INTF LED. Missing load voltage is also reported via the EXTF LED. Diagnostics are not parameterizable — the LEDs indicate the fault type directly. Outputs switch at line frequency (47 Hz nominal) with a turn-on time under 1 ms and turn-off within one AC cycle. There is no zero-crossing switching, so inductive loads may benefit from external snubbers.
Applications
This SM 422 module is used in S7-400 racks to drive AC contactors, solenoid valves, motor starters, and indicator lamps in industrial automation — typical on packaging lines, conveyor systems, and machine tools where 120/230 V AC control circuits are standard.
Lifecycle & availability
The 6ES7422-1FH00-0AA0 is a mature product in the S7-400 family. While Siemens has not formally declared end-of-life for this specific order code, the S7-400 platform is being gradually phased down in favor of the S7-1500 series. Buyers should confirm current availability and lead time via RFQ; surplus and broker channels are the most reliable sources for this module today.