| Article number | 6ES7221-1BF32-0XB0 | 6ES7221-1BH32-0XB0 |
| | Digital Input SM 1221, 8DI, 24V DC | Digital Input SM 1221, 16DI, 24V DC |
| General information | | |
| Product type designation | SM 1221, DI 8x24 V DC | SM 1221, DI 16x24 V DC |
| Supply voltage | | |
| Rated value (DC) | 24 V | 24 V |
| permissible range, lower limit (DC) | 20.4 V | 20.4 V |
| permissible range, upper limit (DC) | 28.8 V | 28.8 V |
| Input current | | |
| from backplane bus 5 V DC, max. | 105 mA | 130 mA |
| Digital inputs | | |
| ● from load voltage L+ (without load), max. | 4 mA; per channel | 4 mA; per channel |
| output voltage / header | | |
| supply voltage of the transmitters / header | | |
| ● product function / supply voltage for transmitters | Yes | Yes |
| Power loss | | |
| Power loss, typ. | 1.5 W | 2.5 W |
| Digital inputs | | |
| Number of digital inputs | 8 | 16 |
| ● in groups of | 2 | 4 |
| Input characteristic curve in accordance with IEC 61131, type 1 | Yes | Yes |
| Number of simultaneously controllable inputs | | |
| all mounting positions | | |
| — up to 40 °C, max. | 8 | 16 |
| horizontal installation | | |
| — up to 40 °C, max. | 8 | 16 |
| — up to 50 °C, max. | 8 | 16 |
| vertical installation | | |
| — up to 40 °C, max. | 8 | 16 |
| Input voltage | | |
| ● Rated value (DC) | 24 V | 24 V |
| ● for signal "0" | 5 V DC at 1 mA | 5 V DC at 1 mA |
| ● for signal "1" | 15 V DC at 2.5 mA | 15 V DC at 2.5 mA |
| Input current | | |
| ● for signal "0", max. (permissible quiescent current) | 1 mA | 1 mA |
| ● for signal "1", min. | 2.5 mA | 2.5 mA |
| ● for signal "1", typ. | 4 mA | 4 mA |
| Input delay (for rated value of input voltage) | | |
| for standard inputs | | |
| — parameterizable | Yes; 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 | Yes; 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 |
| for interrupt inputs | | |
| — parameterizable | Yes | Yes |
| Cable length | | |
| ● shielded, max. | 500 m | 500 m |
| ● unshielded, max. | 300 m | 300 m |
| Interrupts/diagnostics/status information | | |
| Alarms | | |
| ● Diagnostic alarm | Yes | Yes |
| Diagnostics indication LED | | |
| ● for status of the inputs | Yes | Yes |
| Potential separation | | |
| Potential separation digital inputs | | |
| ● between the channels, in groups of | 2 | 4 |
| Degree and class of protection | | |
| IP degree of protection | IP20 | IP20 |