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This is the web edition of the original ⮫ AC500-S safety user manual, version 1.3.2. This web edition is provided for quick reference only. The original safety user manual must be used to meet functional safety application requirements. |
Setting the maximum allowed cycle time of the safety CPU
The SF_WDOG_TIME_SET function block allows the user to monitor the cycle time. The function block must be called by the user during the first cycle. In order to update the outputs ACT_TIME and MAX_TIME, it is necessary to call the function block in each cycle. If the function block is not available in the application, the safety CPU and the application program will enter the SAFE STOP state after the first cycle. The watchdog time is monitored prior to the output of the PROFIsafe telegrams.
If the cycle time is exceeded, an error message is an output and the safety CPU enters the SAFE STOP state. Reasonable values are longer than the typical safety CPU runtime and at least two times shorter than the F_WD_Time of the safety I/O module.
Only one function block instance must be used in the safety program, otherwise a warning is issued.
NOTICE
The cycle time supervision takes place only in RUN (safety) mode.
|
Name |
Data type |
Initial value |
Description, parameter values |
|---|---|---|---|
|
VAR_INPUT |
|||
|
EN |
BOOL |
FALSE |
The function block is activated (EN = TRUE) or deactivated (EN = FALSE) via input EN. If the block is active, the current values are available at the outputs. |
|
WDOG |
DWORD |
16#00000000 |
Watchdog time in ms. The maximum allowed value is 1000. If WDOG is > 1000, then SAFE STOP state will be entered by the safety CPU. |
|
RESET |
BOOL |
FALSE |
TRUE sets MAX_TIME to 0. |
|
VAR_OUTPUT |
|||
|
DONE |
BOOL |
FALSE |
Output DONE indicates that the set process is finished. |
|
ACT_TIME |
DWORD |
16#00000000 |
Actual safety CPU cycle time in ms |
|
MAX_TIME |
DWORD |
16#00000000 |
Maximal monitored safety CPU cycle time in ms |
Call in ST
SF_WDOG_TIME_SET (EN := SF_WDOG_TIME_SET_EN, WDOG := SF_WDOG_TIME_SET_WDOG, RESET := SF_WDOG_TIME_SET_RESET, DONE => SF_WDOG_TIME_SET_DONE, ACT_TIME => SF_WDOG_TIME_SET, MAX_TIME => SF_WDOG_TIME_SET_MAX_TIME);