Siemens S7-1200 System Manual page 938

Technical specifications
A.11 Digital signal boards (SBs)
Technical data
Inductive clamp voltage
Switching delay
Behavior on RUN to STOP
Number of outputs on simultaneously
Cable length (meters)
Because both sinking and sourcing configurations are supported by the same circuitry, the active state of a sourcing
1
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 0 V, which means that a sinking load will be
turned ON.
Note
When switching frequencies above 20 kHz, it is important that the digital inputs receive a
square wave. Consider the following options to improve the signal quality to the inputs:
• Minimize the cable length
• Change a driver from a sink only driver to a sinking and sourcing driver
• Change to a higher quality cable
• Reduce the circuit/components from 24 V to 5 V
• Add an external load at the input
938
SB 1222 DQ 4 x 24 VDC, 200 kHz
None
1.5 μs + 300 ns rise
1.5 μs + 300 ns fall
Last value or substitute value (default
value 0)
2 (no adjacent points) at 60 °C
•
horizontal or 50 °C vertical
4 at 55 °C horizontal or 45 °C
•
vertical
50 shielded twisted pair
SB 1222 DQ 4 x 5 VDC, 200 kHz
None
200 ns + 300 ns rise
200 ns + 300 ns fall
Last value or substitute value (default
value 0)
4
50 shielded twisted pair
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG