Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 777)

L-force | PLC Designer
General Editors

DMS 4.1 EN 03/2011 TD29 775
NOT YET IMPLEMENTED: Possibly the target system defines Singleton Events. These are
events, which only allow to start one single task. Whether such an event starts several
tasks will be checked during compilation of the project. The check notices the data
address of the event variable, not on the name. For example: If the target system
defines %MX1.1 and %IB4 as Singleton-Events, using the following variables as event
variables will produce two detected errors (a and b as well as c and d each have the
same address).
VAR_GLOBAL
a AT %MX1.1: BOOL;
b AT %MX1.1: BOOL;
c AT %MB4: BOOL;
d AT %MD1: BOOL;
END_VAR
Watchdog
For each task a time control (watchdog) can be configured. If the target system
supports an "extended" watchdog configuration, then upper and lower limits as well
as a default for the watchdog time and a time definition in percent might be
predefined by the device description.
Enable: When this option is activated ( ), the watchdog is enabled. This means that
the task will be terminated in error status ("exception"), if the currently set watchdog
Time (see below) gets exceeded, whereby there is taken account of the currently set
Sensitivity (see below). If option "Update IO while in stop" is enabled in the PLC
Settings dialog, the outputs will be set to the predefined default values.
The following cases are possible:
1.Contiguous time overruns; the following is true:
Sensitivity Exception in cycle...
0, 1, 2 1
3 2
... ...
n n-1