Fault detection by testing
The following faults can be detected by testing an element:
•
Faults in electronic sensors with test inputs.
•
Short-circuits between any of the test outputs.
Using a test pulse frequency of ≥ 200 ms and a test pulse duration of 2 ms, you
can detect a cross-circuit between the test outputs of 12 sequential modules.
Using a test pulse frequency of ≥ 8 ms and a test pulse duration of 2 ms, you can
detect a cross-circuit between any two sequential test output pairs of a module.
•
Short circuits to 24 V DC (to High) on inputs that are connected to test outputs,
regardless of the length of the test gaps and the test periods.
•
Sensor wiring short-circuits to 24 V that could interfere with a switch-off condition.
The following faults cannot be detected:
•
Short circuits between test outputs and the associated input.
Further topics
•
"Configuring elements", page 51
4.5.3
Safety outputs
Important information
WARNING
Ineffectiveness of the protective device
In the event of a fault, a single safety output (Q) can switch off after a delay or briefly
switch to High. The response time increases depending on the configuration of the
output. The dangerous state may not be stopped or not be stopped in a timely manner
in the event of non-compliance.
b
Take the increased response time into consideration in the risk analysis.
b
Take the possible reduced safety level into consideration in the risk analysis.
Fault detection by testing
The following faults can be detected by testing an element:
•
Short-circuits between any of the safety outputs.
You can detect a cross-circuit between the safety outputs of 12 sequential mod‐
ules.
•
Short circuits to 24 V DC (to High) on safety outputs.
•
Actuator wiring short-circuits to 24 V.
Further topics
•
•
"Configuring elements", page 51
4.6
Integration into the controller network
4.6.1
Network topology
The Modbus® TCP interface is suitable for the following network topologies:
•
Star
•
Tree
4
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O P E R A T I N G I N S T R U C T I O N S | Flexi Compact
8024589/2020-11-10 | SICK
Subject to change without notice
