| General information |
| Product type designation | SM 1221, DI 16x 24 V DC |
| Input current |
| from backplane bus 5 V DC, max. | 90 mA |
| Digital inputs |
| ● from load voltage L+ (without load), max. | 4.1 mA; per channel |
| Power loss |
| Power loss, typ. | 3.2 W |
| Digital inputs |
| Number of digital inputs | 16 |
| ● in groups of | 4 |
| Input characteristic curve in accordance with IEC 61131, type 1 | Yes |
| Number of simultaneously controllable inputs |
| horizontal installation |
| — up to 40 °C, max. | 16 |
| — up to 50 °C, max. | 16 |
| vertical installation |
| — up to 40 °C, max. | 16 |
| Input voltage |
| ● Rated value (DC) | 24 V |
| ● for signal "0" | 5 V DC or 0.5 mA |
| ● for signal "1" | 15 V DC at 2.5 mA |
| Input current |
| ● for signal "0", max. (permissible quiescent current) | 0.5 mA |
| ● for signal "1", min. | 2.5 mA |
| ● for signal "1", typ. | 4.1 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 |
| for interrupt inputs |
| — parameterizable | No |
| Cable length |
| ● shielded, max. | 500 m |
| ● unshielded, max. | 300 m |
| Interrupts/diagnostics/status information |
| Diagnostics function | Yes |
| Alarms |
| ● Diagnostic alarm | No |
| Diagnoses |
| ● Monitoring the supply voltage | No |
| Diagnostics indication LED |
| ● for status of the inputs | Yes |
| ● for maintenance | Yes |
| Potential separation |
| Potential separation digital inputs |
| ● between the channels, in groups of | 4 |
| ● between the channels and backplane bus | Yes; 707 V DC (type test) |
| Isolation |
| Isolation tested with | 707 V DC (type test) |
| Degree and class of protection |
| IP degree of protection | IP20 |
| Standards, approvals, certificates |
| Siemens Eco Profile (SEP) | Siemens EcoTech |
| CE mark | Yes |
| CSA approval | No |
| UL approval | Yes |
| cULus | Yes |
| FM approval | No |
| RCM (formerly C-TICK) | Yes |
| KC approval | Yes |
| Marine approval | No |
| Ecological footprint |
| ● environmental product declaration | Yes; type 2 acc. to ISO 14021 |
| Global warming potential |
| — global warming potential, (total) [CO2 eq] | 40.3 kg |
| — global warming potential, (during production) [CO2 eq] | 7.79 kg |
| — global warming potential, (during operation) [CO2 eq] | 32.5 kg |
| — global warming potential, (after end of life cycle) [CO2 eq] | -0.089 kg |
| Ambient conditions |
| Free fall |
| ● Fall height, max. | 0.3 m; five times, in product package |
| Ambient temperature during operation |
| ● horizontal installation, min. | -20 °C |
| ● horizontal installation, max. | 60 °C; at max. voltages and max. specification |
| ● vertical installation, min. | -20 °C |
| ● vertical installation, max. | 50 °C; at max. voltages and max. specification |
| Ambient temperature during storage/transportation |
| ● min. | -40 °C |
| ● max. | 70 °C |
| Air pressure acc. to IEC 60068-2-13 |
| ● Operation, min. | 540 hPa |
| ● Operation, max. | 1 140 hPa |
| ● Storage/transport, min. | 540 hPa |
| ● Storage/transport, max. | 1 140 hPa |
| Altitude during operation relating to sea level |
| ● Installation altitude, min. | -1 000 m |
| ● Installation altitude, max. | 5 000 m; Restrictions for installation altitudes > 2 000 m, see manual |
| Relative humidity |
| ● Operation at 25 ℃ without condensation, max. | 95 % |
| Vibrations |
| ● Vibration resistance during operation acc. to IEC 60068-2-6 | 3.5 mm from 5 - 8.4 Hz, 1g from 8.4 - 150 Hz |
| ● Operation, tested according to IEC 60068-2-6 | Yes |
| Shock testing |
| ● tested according to IEC 60068-2-27 | Yes; IEC 68, Part 2-27 half-sine: strength of the shock 15 g (peak value), duration 11 ms |
| Pollutant concentrations |
| ● SO2 at RH < 60% without condensation | S02: < 0.5 ppm; H2S: < 0.1 ppm; RH < 60 % condensation-free |
| connection method |
| required front connector | No |
| Mechanics/material |
| Enclosure material (front) | |
| ● Plastic | Yes |
| Dimensions |
| Width | 30 mm |
| Height | 125 mm |
| Depth | 100 mm |
| Weights |
| Weight, approx. | 166 g |