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4 Safety Function Blocks
NX-series Safety Control Unit Instructions Reference Manual (Z931)
4
SF_SafetyRequest
Error Detected
The FB detects the following errors.
• When the actuator does not enter the safe state within the monitoring time
• When the acknowledge signal is not sent before the request becomes invalid
• For an always-TRUE Reset signal
• When an undetected change to TRUE in the Reset input is detected when the acknowledge sig-
nal is lost or the monitoring time is exceeded
FB External Errors:
There are no external errors because error bits and error information are not provided by a normal
actuator.
Operation for Errors
• When an error occurs, the S_SafetyActive output is set to FALSE.
• Acknowledgment by changing the Reset input to TRUE is required for an error. After this reset,
the S_OpMode request must be set to TRUE to enable the FB to continue functioning.
FB-specific Error Codes
Instruction Execution Errors
DiagCode (hexadecimal)
DiagCode
(decimal)
Status name Status description and output results
C002 49154 Acknowledge Lost The acknowledge signal was lost in the Safe state.
Ready = TRUE
S_SafetyActive = FALSE
S_SafetyRequest = FALSE
Error = TRUE
C003 49155 MonitoringTime
Elapsed
The S_OpMode input request was not completed
within MonitoringTime.
Ready = TRUE
S_SafetyActive = FALSE
S_SafetyRequest = FALSE
Error = TRUE
C004 49156 Reset Error 2 When the Acknowledge Lost state was entered, an
undetected change to TRUE in the Reset input
was detected.
Ready = TRUE
S_SafetyActive = FALSE
S_SafetyRequest = FALSE
Error = TRUE
C005 49157 Reset Error 3 When the Monitoring Time Elapsed state was
entered, an undetected change to TRUE in the
Reset input was detected.
Ready = TRUE
S_SafetyActive = FALSE
S_SafetyRequest = FALSE
Error = TRUE