| SIMATIC S7-1200, DIGITAL INPUT SM 1221, 16 DI, 24VDC, SINK/SOURCE INPUT |
| Supply voltage |
| 24 V DC | Yes |
| 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 |
| Digital inputs |
| from load voltage L+ (without load), max. | 4 mA; per channel |
| Output voltage |
| Power supply to the transmitters |
| present | Yes |
| Power losses |
| Power loss, typ. | 2.5 W |
| Digital inputs |
| Number/binary inputs | 16 |
| In groups of | 4 |
| Input characteristic curve acc. to IEC 1131, Type 1 | Yes |
| Number of simultaneously controllable inputs |
| all mounting positions |
| up to 40 °C, max. | 16 |
| horizontal installation |
| up to 40 °C, max. | 16 |
| up to 50 °C, max. | 16 |
| vertical installation |
| up to 40 °C, max. | 16 |
| Input voltage |
| Type of input voltage | DC |
| Rated value, DC | 24 V |
| for signal "0" | 5 V DC at 1 mA |
| for signal "1" | 15 V DC at 2.5 mA |
| Input current |
| for signal "0", max. (permissible quiescent current) | 1 mA |
| for signal "1", min. | 2.5 mA |
| for signal "1", typ. | 4 mA; Typical |
| Input delay (for rated value of input voltage) |
| for standard inputs |
| Parameterizable | Yes; 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, and 12.8 ms, selectable in groups of four |
| for interrupt inputs |
| Parameterizable | Yes |
| Cable length |
| Cable length, shielded, max. | 500 m |
| Cable length unshielded, max. | 300 m |
| Digital outputs |
| Number/binary outputs | 0 |
| Interrupts/diagnostics/status information |
| Alarms |
| Alarms | Yes |
| Diagnostic alarm | Yes |
| Diagnoses |
| Diagnostic functions | Yes |
| Diagnostics indication LED |
| for status of the inputs | Yes |
| for maintenance | Yes |
| Status indicator digital input (green) | Yes |
| Galvanic isolation |
| Galvanic isolation digital inputs |
| between the channels, in groups of | 4 |
| Climatic and mechanical conditions for storage and transport |
| Climatic conditions for storage and transport |
| Free fall |
| Drop height, max. (in packaging) | 0.3 m; five times, in dispatch package |
| Temperature |
| Permissible temperature range | -40 °C to +70 °C |
| Air pressure acc. to IEC 60068-2-13 |
| Permissible air pressure | 1080 to 660 hPa |
| Mechanical and climatic conditions during operation |
| Climatic conditions in operation |
| Temperature |
| Permissible temperature range | 0 °C to 55 °C horizontal installation 0 °C to 45 °C vertical installation |
| Permissible temperature change | 5°C to 55°C, 3°C / minute |
| Degree and class of protection |
| IP20 | Yes |
| Standards, approvals, certificates |
| CE mark | Yes |
| C-TICK | Yes |
| FM approval | Yes |
| Connection method |
| required front connector | Yes |
| Mechanics/material |
| Type of housing (front) | |
| Plastic | Yes |
| Dimensions |
| Width | 45 mm |
| Height | 100 mm |
| Depth | 75 mm |
| Weight |
| Weight, approx. | 210 g |
