Fault reaction function
Definition: A safety function requires a “fault reaction function” that tries to initiate a safe
state if it detects a failure in the safety system.
The fault reaction function of the emergency stop safety relay trips the system, if it detects
a failure in the safety circuit (for example, short circuit between signals, open circuit, or
redundancy fault).
If a fault is detected, the fault reaction function:
• activates the emergency stop command
• activates the STO function
• opens the main contactor/breaker
• keeps the safe state activated and the emergency stop reset button indication lamp on
until the fault is repaired and the safety function is reset.
Note: Resetting the safety function is not possible, if the reset circuit in the emergency stop
safety relay is open.
If the reset button [S62] is pressed for more than 10 seconds, the emergency stop safety
relay [A61] goes into a fault state. If this occurs, the user must reset the safety relay. See
the fault tracing instructions in this manual.
Hardware settings
Set the time delay of the emergency stop safety relay [A61] according to the application
needs with the rotary switches on the safety relay.
DescriptionValueSwitch
Selects the delay mode. Must be 1.1t
Fkt
Selects the time range (in seconds)
for the delayed contacts.
User-definedt
max
Value range: 1 … 300 s.
Adjusts the time within the selected
range in 10% steps.
User-definedt
Value range: 0.1…1.
Example: If the required time (t
v
) is 30 s, set:
• t
max
= 30 s and t = 1 (t
v
= t
max
· t = 30 s · 1 = 30 s), or
• t
max
= 300 s and t = 0.1 (t
v
= t
max
· t = 300 s · 0.1 = 30 s).
Set the delay for the emergency stop safety relay [A61] a little longer than the emergency
stop deceleration time defined by drive parameters 23.23 and 46.01 or 46.02. See chapter
Parameter settings (page 29).
26 Option description
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