Crosstalk Of Digital Input/Output Signals; Additional Rules And Instructions For Operation With Motor Starters; Protection Against Short Circuit - Siemens Simantic ET200SP System Manual

5.2.3

Crosstalk of digital input/output signals

When fail-safe digital output and input signals are in a single cable, F-DQ modules and F-
PM-E modules may experience readback errors.
Cause: capacitive crosstalk
During the bit pattern test of the outputs or the sensor supply of the inputs, the steep
switching edge of the output drivers caused by the coupling capacitance of the line may
result in crosstalk to other non-activated output or input channels. This may then lead to a
response of the readback circuit in these channels. A cross circuit/short-circuit is detected,
which leads to safety-related tripping.
Remedy:
● Separate cables for F-DI modules, F-DQ modules, and F-PM-E modules or non-fail-safe
DQ modules
● Separate cables for F-DQ channel and F-DI channels for the F-PM-E module
● Coupling relay or diodes in the outputs
● Disable the sensor supply test if safety class requirements allow it.
Cause: magnetic crosstalk
Note that an inductive load connected to the F-DQ channels can induce coupling of a strong
magnetic field.
Remedy:
● Separate the inductive loads spatially or shield against the magnetic field.
● Configure the readback time to 50 ms or higher.
5.3

Additional rules and instructions for operation with motor starters

5.3.1

Protection against short circuit

The motor starter complies with type of coordination 1. Secure the feeder cable for the infeed
bus according to current, country-specific rules for conductor protection.
Hazardous Voltage at the Motor
Can Cause Death, Serious Injury, or Property Damage.
Following a short-circuit, the SIMATIC ET 200SP motor starter is defective. Replace the
motor starter following a short-circuit.
Distributed I/O system
System Manual, 12/2016, A5E03576849-AG
5.3 Additional rules and instructions for operation with motor starters
WARNING
Wiring
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