SIMATIC S7-400 SM 421, DI 32xUC 120 V
$1,540.48 – $1,711.64
SM 421 digital input module — 32 isolated channels, 120V AC/DC universal current input. [VERIFIED via Siemens official datasheet]
Technical Specifications
| Module Type | Digital Input |
| Channels | 32, isolated |
| Input Voltage | 120V, UC (universal current = AC or DC) |
| Cable Length | Up to 600m unshielded / 1000m shielded |
Typical Applications
Used to sense 120V AC or DC field signals directly without an external signal converter, suited for installations where field devices are wired at 120V rather than the more common 24V DC level.





