553BTechnical specifications
A.8 Digital signal boards (SBs)
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
721
NOTICE
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
Table A- 110 Wiring diagrams for the 200 kHz digital input SBs
SB 1221 DI 4 x 24 VDC, 200 kHz
(6ES7 221-3BD30-0XB0)
SB 1221 DI 4 x 5 VDC, 200 kHz
(6ES7 221-3AD30-0XB0)
①
Supports sourcing inputs only