Key Features
- 16 digital inputs: SM 1221, DI 16×24 V DC with 16 digital inputs in groups of 4.
- 24 V DC input level: Rated value (DC): 24 V; input voltage for signal "0": 5 V DC at 1 mA; input voltage for signal "1": 15 V DC at 2.5 mA.
- Selectable input filtering: Parameterizable with 0.2 ms, 0.4 ms, 0.8 ms, 1.6 ms, 3.2 ms, 6.4 ms and 12.8 ms, selectable in groups of four.
- Diagnostic support: Diagnostic alarm: Yes; diagnostics indication LED for status of the inputs: Yes.
- Conformal coating: Conformally coated version based on 6ES7221-1BH32-0XB0 for high reliability.
- Required front connector: Connection method: required front connector.
Applications
- Digital input signal acquisition: For acquiring 16 digital input signals at 24 V DC in groups of 4.
- Interrupt input monitoring: For parameterizable interrupt inputs with diagnostic alarm support and status indication LED.
Technical Summary
| Product type designation | SM 1221, DI 16×24 V DC |
|---|---|
| Based on | 6ES7221-1BH32-0XB0 |
| Number of digital inputs | 16 |
| Input groups | 4 |
| Rated value (DC) | 24 V |
| Permissible range, lower limit (DC) | 20.4 V |
| Permissible range, upper limit (DC) | 28.8 V |
| Input current from backplane bus 5 V DC, max. | 130 mA |
| Input current from load voltage L+ (without load), max. | 4 mA; per channel |
| Power loss, typ. | 2.5 W |
| Input characteristic curve in accordance with IEC 61131, type 1 | Yes |
| Input voltage for signal "0" | 5 V DC at 1 mA |
| Input voltage for signal "1" | 15 V DC at 2.5 mA |
| Diagnostics indication LED for status of the inputs | Yes |
Frequently Asked Questions
What is Siemens 6AG1221-1BH32-4XB0 used for?
It is a SIPLUS S7-1200 SM 1221 digital input module with 16 DI at 24 V DC.
How many digital inputs does this module have?
It has 16 digital inputs arranged in groups of 4.
What electrical input data define the module?
Rated value is 24 V DC, with a permissible range of 20.4 V to 28.8 V DC.
Does the module support diagnostics for its inputs?
Yes. Diagnostic alarm and diagnostics indication LED for input status are both provided.
What should be checked before selection?
Check the 16 DI count, 24 V DC input rating, sink/source behavior, required front connector, and the -20…+60 °C operating range.
