Overview
The 6ES7421-7BH01-0AB0 is a Siemens SM 421 digital input module for the S7-400 platform, offering 16 inputs rated for 24 V DC with a signal-1 threshold of 11 V DC to 30 V DC and a typical input current of 6 mA per channel.
Siemens 6ES7421-7BH01-0AB0 SM 421 digital input module, 16 DI, 24 V DC
MPN6ES7421-7BH01-0AB0
NRND
Siemens 6ES7421-7BH01-0AB0 — now in phase-out and being discontinued, supplied from remaining surplus and broker stock.
$558.80 – $744.00Ref. price · indicative, final on quote
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jun 2026
Specifications
| Parameter | Value |
|---|---|
| Digital inputs | 16 |
| Parameter | Value |
|---|---|
| Rated value (DC) | 24 V |
| Permissible range, lower limit (DC) | 20.4 V |
| Permissible range, upper limit (DC) | 28.8 V |
| For signal "1" | 11 V DC to 30 V DC |
| For signal "0" | -30 V DC to +5 V DC |
| Current for signal "1" (typ.) | 6 mA; 6 to 8 mA |
| Power loss (typ.) | 5 W |
| Current consumption from backplane bus (5 V DC), max. | 130 mA |
| Short-circuit protection | Yes; Electronic |
| Reverse polarity protection | Yes |
| Isolation test voltage | 500 V DC |
| Isolation: between channels | Yes |
| Isolation: channels to backplane bus | Yes |
| Max. cable length, shielded | 1 000 m; 1 000 m: 3 ms, 70 m: 0.5 ms, 30 m: 0.1 ms, 30 m: 0.05 ms |
| Max. cable length, unshielded | 600 m; 600 m: 3 ms; 50 m: 0,5 ms; 20 m: 0,1 ms; 20 m: 0,05 ms |
| Parameter | Value |
|---|---|
| Parameterizable | Yes |
| Diagnostic alarm | Yes; Parameterizable |
| Diagnostics function | Yes; Parameterizable |
| Parameter | Value |
|---|---|
| Height | 290 mm |
| Width | 25 mm |
| Depth | 210 mm |
| Weight (approx.) | 600 g |
Product details
MPN
6ES7421-7BH01-0AB0