12/2008 3 Setting up functions
3.4 Fault services
© Siemens AG 2008 All Rights Reserved
ePS Network Services, Function Manual (FH) - Release 12/2008
3-117
Field Content Type
value acting as a trigger if the time is
exceeded for a started process which
is not yet stopped..
For all units, up to 3-digit numerical
values can be specified. With days, the
limit is 366.
INPUT
(Digits from
1 to -999)
Monitoring time
unit
Available selection:
- Milliseconds
- Seconds
- Minutes
- Hours
- Days
DISPLAY
SELECTION
3.4.7 Machine trigger on "new value of ePS variable"
Description of functions
The stopwatch offers the possibility to monitor actions and functions that could not
take place in the defined time window intended or specified for them. A potential
overshooting or undershooting of the defined time window can be detected at an
early stage.
Using a definable start and stop signal from the PLC, the real time difference is
determined and maintained as a variable in a time series. The permissible time
range can be delimited with additional triggers on upper and lower limits and for
prewarning and warning. In addition to simply maintaining a time series via the
variable monitor, the stopwatch trigger can also use it to trigger all other available
actions. The same variable or different variables can be used as a start and stop
signal, with all of the comparison operators that are permissible for PLC variables.
Notice
Due to system dependencies, repeatability of the stopwatch function is linked to
the communication runtimes, which depend on the demands placed on the
interface between PLC and PC of the operator. As a rule, repetitions of less than
one second can be achieved; with high interface demands it may however be a
few seconds.
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