Name: 6ES7421-1FH20-0AA0
Brand: Siemens
SKU: 6ES7421-1FH20-0AA0
Availability: LimitedAvailability

Specifications

Inputs

6ES7421-1FH20-0AA0 — Inputs
Parameter	Value
Number of digital inputs	16
2-wire sensor support	Yes

Electrical

6ES7421-1FH20-0AA0 — Electrical
Parameter	Value
Input voltage at signal "1"	74 to 264 V AC; 80 to 264 V DC, -80 to -264 V
Input voltage type (AC/DC)	AC/DC
Input voltage at signal "0"	0 to 40 V AC/ -40 to +40 V DC
Input current at signal "1" (typ.)	10 mA; at 120 V: 10 mA AC, 1.8 mA DC; at 230 V: 14 mA AC, 2 mA DC
Input current at signal "0", max. (permissible quiescent current)	6 mA; AC: 6 mA; DC: 2 mA
Power loss (typ.)	12 W
Current consumption from backplane bus (5 V DC), max.	80 mA
Permissible quiescent current, 2-wire sensor, max.	5 mA; AC: 5 mA
Cable length, unshielded, max.	600 m
Cable length, shielded, max.	1 000 m

Timing

6ES7421-1FH20-0AA0 — Timing
Parameter	Value
Input delay 0 to 1, max.	20 ms; AC: 20 ms; DC: 15 ms
Input delay 1 to 0, max.	30 ms; AC: 30 ms; DC: 25 ms

Diagnostics & Isolation

6ES7421-1FH20-0AA0 — Diagnostics & Isolation
Parameter	Value
Diagnostics function	No
Isolation between channels	Yes
Isolation between channels and backplane bus	Yes
Isolation test voltage	1 500 V AC
Channels per isolated group	4
Status indicator per channel (green)	Yes

Mechanical

6ES7421-1FH20-0AA0 — Mechanical
Parameter	Value
Depth	210 mm
Height	290 mm
Width	25 mm

Product details

Overview

The 6ES7421-1FH20-0AA0 is a Siemens SM 421 digital input module for the S7-400 rack, providing 16 isolated inputs that accept UC 120/230 V (47...63 Hz) and comply with IEC 1131-2 Type 2. It draws 12.0 W from the backplane and fits a 25 mm wide slot, with a signal threshold of 74 to 264 V AC or 80 to 264 V DC for the 1-signal.

Lifecycle and sourcing

Siemens phased out the 6ES7421-1FH20-0AA0 effective 2025-10-01; no official successor is listed in the evidence. Remaining units are available through surplus and broker channels.

Specifications

Inputs

6ES7421-1FH20-0AA0 — Inputs
Parameter	Value
Number of digital inputs	16
2-wire sensor support	Yes

Electrical

6ES7421-1FH20-0AA0 — Electrical
Parameter	Value
Input voltage at signal "1"	74 to 264 V AC; 80 to 264 V DC, -80 to -264 V
Input voltage type (AC/DC)	AC/DC
Input voltage at signal "0"	0 to 40 V AC/ -40 to +40 V DC
Input current at signal "1" (typ.)	10 mA; at 120 V: 10 mA AC, 1.8 mA DC; at 230 V: 14 mA AC, 2 mA DC
Input current at signal "0", max. (permissible quiescent current)	6 mA; AC: 6 mA; DC: 2 mA
Power loss (typ.)	12 W
Current consumption from backplane bus (5 V DC), max.	80 mA
Permissible quiescent current, 2-wire sensor, max.	5 mA; AC: 5 mA
Cable length, unshielded, max.	600 m
Cable length, shielded, max.	1 000 m

Timing

6ES7421-1FH20-0AA0 — Timing
Parameter	Value
Input delay 0 to 1, max.	20 ms; AC: 20 ms; DC: 15 ms
Input delay 1 to 0, max.	30 ms; AC: 30 ms; DC: 25 ms

Diagnostics & Isolation

6ES7421-1FH20-0AA0 — Diagnostics & Isolation
Parameter	Value
Diagnostics function	No
Isolation between channels	Yes
Isolation between channels and backplane bus	Yes
Isolation test voltage	1 500 V AC
Channels per isolated group	4
Status indicator per channel (green)	Yes

Mechanical

6ES7421-1FH20-0AA0 — Mechanical
Parameter	Value
Depth	210 mm
Height	290 mm
Width	25 mm

Product details

Overview

Lifecycle and sourcing

Siemens phased out the 6ES7421-1FH20-0AA0 effective 2025-10-01; no official successor is listed in the evidence. Remaining units are available through surplus and broker channels.

Siemens 6ES7421-1FH20-0AA0 SM 421 digital input module, 16 DI, UC 120/230 V

Specifications

Inputs

Electrical

Timing

Diagnostics & Isolation

Mechanical

Product details

Overview

Lifecycle and sourcing

Siemens 6ES7421-1FH20-0AA0 SM 421 digital input module, 16 DI, UC 120/230 V

Specifications

Inputs

Electrical

Timing

Diagnostics & Isolation

Mechanical

Product details

Overview

Lifecycle and sourcing

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