Overview
The 6ES7422-1BL00-0AA0 is a Siemens SM 422 digital output module for the S7-400 programmable logic controller platform, providing 32 digital outputs rated at 0.5 A each with a Profibus interface for integration into the rack-based backplane. It operates on a 24 V DC supply, measures 290 x 25 x 210 mm, weighs 600 g, and is rated IP20 for installation in a protected control cabinet on a rack-mount backplane.
Function & operation
This module switches 32 digital outputs, each capable of 0.5 A continuous current, with a minimum load resistance of 48 Ω and a maximum of 4 kΩ. The signal-1 voltage at the output is L+ minus 0.3 V, ensuring a clean ON-state voltage drop. Switching times are symmetrical at 1 ms for both turn-on and turn-off, making it suitable for moderate-speed discrete control tasks such as valve actuation, contactor drives, and indicator banks. The module communicates over Profibus, relying on the S7-400 CPU for program execution and diagnostics.
Applications
The SM 422 digital output module is used in Siemens S7-400-based automation systems for medium-to-large process and manufacturing lines — chemical batch plants, power generation auxiliaries, water treatment skids, and material handling systems — where a high density of 32 discrete outputs per slot is needed to drive solenoids, motor starters, and status indicators.