Sensitivity
Exception in cycle...
0, 1, 2
1
3
2
...
...
n
n-1
One-time timeout:
Exception when the cycle time of the current cycle is longer than "time × sen‐
sitivity".
Example:
Time="t#10ms", sensitivity="5"
⇒ Exception as soon as the task (one-time) runs longer than 50 ms.
Please note that a watchdog can be switched off for certain PLC cycles using
the "CmpIecTask.library" functions, which is useful for cycles that can take
more time due to initializations.
Switch a watchdog off or on as follows:
1.
Declare a suitable variable for the task handle (
RTS_IEC_HANDLE
type):
Program:
hIecTask : RTS_IEC_HANDLE;
2.
Use the interface functions to switch off a watchdog (and switch it on
again afterwards):
Program:
hIecTask := IecTaskGetCurrent(0);
IecTaskDisableWatchdog(hIecTask);
... // Code that is protected against watchdog
IecTaskEnableWatchdog(hIecTask);
4.5.6
Runtime measurements
There are various ways to determine the required time in MLD. The system
automatically measures and statistically evaluates the task runtimes. In addi‐
tion, the remaining time is measured in every PLC time slot.
Measuring task runtimes in milli‐
seconds
The task runtimes can be evaluated using a function in the PLC program.
This function is "SysTaskGetInfo" with the "SYS_TASK_INFO" structure in
the "SysTask" library. This provides the runtime of the desired task as a
structure with statistics.
Include the maximum and average runtime when evaluating:
●
If a one-time timeout already causes problems and is to be monitored,
the maximum runtime "dwCycleTimeMax" has to be used for evaluation
(corresponds to watchdog sensitivity "1"). The ratio of maximum time to
watchdog time indicates the load of the corresponding task. Make sure
that the load is not too high (e.g., not above 50%) for subsequent firm‐
ware updates that may require slightly more processing power, and pri‐
marily for future program enhancements.
DOK-INDRV*-MLD3-**VRS*-AP02-EN-P
Bosch Rexroth AG
65/267
Rexroth IndraDrive Rexroth IndraMotion MLD (2G) as of MPx-18
Basic functions of Rexroth IndraMotion MLD
LSA Control S.L. www.lsa-control.com [email protected] (+34) 960 62 43 01