SIMATIC S7-1200, Digital input SM 1221, 16 DI, 24 V DC, Sink/Source General information Product type designation SM 1221, DI 16x24 V DC Supply voltage 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 Digital inputs ● from load voltage L+ (without load), max. 4 mA; per channel Output voltage Power supply to the transmitters ● present Yes Power loss Power loss, typ. 2.5 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 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 ● 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 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 Yes Cable length ● shielded, max. 500 m ● unshielded, max. 300 m Interrupts/diagnostics/status information Alarms ● Diagnostic alarm Yes Diagnostics indication LED ● for status of the inputs Yes Potential separation Potential separation digital inputs ● between the channels, in groups of 4 Degree and class of protection IP degree of protection IP20 Standards, approvals, certificates CE mark Yes CSA approval Yes UL approval Yes cULus Yes FM approval Yes RCM (formerly C-TICK) Yes KC approval Yes Marine approval Yes Ecological footprint ● environmental product declaration Yes Global warming potential — global warming potential, (total) [CO2 eq] 123 kg — global warming potential, (during production) [CO2 eq] 12.1 kg — global warming potential, (during operation) [CO2 eq] 111 kg — global warming potential, (after end of life cycle) [CO2 eq] -0.434 kg Ambient conditions Free fall ● Fall height, max. 0.3 m; five times, in product package Ambient temperature during operation ● min. -20 °C ● max. 60 °C ● permissible temperature change 5°C to 55°C, 3°C / minute Ambient temperature during storage/transportation ● min. -40 °C ● max. 70 °C Air pressure acc. to IEC 60068-2-13 ● Storage/transport, min. 660 hPa ● Storage/transport, max. 1 080 hPa Relative humidity ● Operation at 25 ℃ without condensation, max. 95 % Connection method required front connector Yes Mechanics/material Enclosure material (front) ● plastic Yes Dimensions Width 45 mm Height 100 mm Depth 75 mm Weights Weight, approx. 210 g
