| | SIMATIC S7-300, DIGITAL INPUT SM 321, OPTICALLY ISOLATED, 16DI, 24 V DC, 1 X 20 PIN |
| |
| Supply voltage |
| Load voltage L+ |
| 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. | 10 mA |
| Power losses |
| Power loss, typ. | 3.5 W |
| Digital inputs |
| Number/binary inputs | 16 |
| Input characteristic curve acc. to IEC 61131, Type 1 | Yes |
| Number of simultaneously controllable inputs |
| horizontal installation |
| up to 40 °C, max. | 16 |
| up to 60 °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" | -30 to +5 V |
| for signal "1" | 13 to 30 V |
| Input current |
| for signal "1", typ. | 7 mA |
| Input delay (for rated value of input voltage) |
| for standard inputs |
| Parameterizable | No |
| at "0" to "1", min. | 1.2 ms |
| at "0" to "1", max. | 4.8 ms |
| Cable length |
| Cable length, shielded, max. | 1000 m |
| Cable length unshielded, max. | 600 m |
| Encoder |
| Connectable encoders |
| 2-wire sensor | Yes |
| Permissible quiescent current (2-wire sensor), max. | 1.5 mA |
| Isochronous mode |
| Isochronous operation (application synchronized up to terminal) | No |
| Interrupts/diagnostics/status information |
| Alarms |
| Alarms | No |
| Diagnostic alarm | No |
| Hardware interrupt | No |
| Diagnostic messages |
| Diagnostic functions | No |
| Diagnostics indication LED |
| Status indicator digital input (green) | Yes |
| Galvanic isolation |
| Galvanic isolation digital inputs |
| between the channels | No |
| between the channels, in groups of | 16 |
| between the channels and the backplane bus | Yes; Optocoupler |
| Permissible potential difference |
| between different circuits | 75 VDC / 60 VAC |
| Isolation |
| Isolation checked with | 500 V DC |
| Connection method |
| required front connector | 20-pin |
| Dimensions |
| Width | 40 mm |
| Height | 125 mm |
| Depth | 120 mm |
| Weight |
| Weight, approx. | 200 g |
| Status | Mar 12, 2012 |
