Siemens Sinamics S110 Function Manual page 335

F-DI features
● Failsafe configuration with two digital inputs per F-DI
● Input filter for test signals with a dark period of less than 1 ms
● Configurable connection of NC/NC or NC/NO contacts by means of parameter p10140
● Status parameter r0722
● Adjustable time window for monitoring discrepancy at both digital inputs by means of
● 2. Digital input with additional tap of the optocoupler cathode for connecting an M-
The inclusion of additional load resistors makes it possible to use digital outputs with larger
residual currents to connect CU305 inputs.
● F-DI = safety-related dual-channel digital input
● F-DO = safety-related dual-channel digital output
If the digital outputs from another device (e.g. F-DOs on a safety PLC) with a residual current
greater than 0.5 mA when "OFF" are connected to the CU305 F-DIs, load resistors should
be connected in parallel to both connections on the F-DI.
The maximum permissible voltage for a CU305 F-DI when "OFF" is 5 V (in accordance with
IEC 61131-2, 2008).
Figures
- "F-DI at plus-minus-switching safe output ..." and
- "F-DI at plus-plus-switching safe output ..."
in the section titled "Input/output interconnections for a safety relay with CU305" show
exactly how the protective circuits for F-DIs with additional load resistors are wired.
Drive functions
Function Manual, 10/2008, 6SL3097-4AB10-0BP0
parameter p10002 for all F-DIs
switching output of a failsafe controller.
WARNING
In contrast to mechanical switching contacts (e.g. EMERGENCY STOP switches),
leakage currents can still flow on semiconductor switches such as those usually used at
digital outputs even when they have been switched off. This can lead to false switching
states if digital inputs are not connected correctly.
The conditions for digital inputs/outputs specified in the relevant manufacturer
documentation must be observed.
WARNING
In accordance with IEC 61131 Part 2, Chapter 5.2 (2008), only outputs that have a
maximum residual current of 0.5 mA when "OFF" can be used to connect CU305 digital
inputs with digital semiconductor outputs.
Safety Integrated Functions
8.6 Controlling the safety functions
335