Siemens SIMATIC S7-1200 Manual page 244

Technical specifications
A.3 Digital I/O modules
Table A- 15 Wiring diagrams for digital SBs
SB 1221 input module
SB 1221 DI 4 (200 kHz)
①
Supports sourcing inputs only.
Note
The high-speed (200 kHz) SBs (SB 1221 and SB 1223) support only sinking inputs. The
standard SB 1223 supports only sourcing inputs.
The high-speed (200 kHz) outputs (SB 1222 and SB 1223) can be either sourcing or sinking.
For sourcing outputs, connect "Load" to "-" (shown). For sinking outputs, connect "Load" to
"+". Because both sinking and sourcing configurations are supported by the same circuitry,
the active state of a sourcing load is opposite that of a sinking load. A source output exhibits
positive logic (Q bit and LED are ON when the load has current flow), while a sink output
exhibits negative logic (Q bit and LED are OFF when the load has current flow). If the
module is plugged in with no user program, the default for this module is 0V, which means
that a sinking load will be turned ON.
244
SB 1222 output module
SB 1222 DQ 4 (200 kHz)
①
For sourcing outputs, connect
"Load" to "-" (shown). For sinking
outputs, connect "Load" to "+".
SB 1223 input/output module
SB 1223 DI 2 / DQ2 (200 kHz)
①
Supports sourcing inputs only.
②
For sourcing outputs, connect
"Load" to "-" (shown). For sinking
outputs, connect "Load" to "+".
Manual, 11/2011, A5E02486774-04
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