User Manual

CM2N8890en / 01.05.02 Siemens Building Technologies
2/2 Building Automation
Functioning
The BPS has two reaction tasks for event handling:
• TSK 253 for reactions due to EMC changes. Parameter EMV = Event Main Value,
i.e., the main value for triggering the event.
• TSK 252 for reactions triggered by changes to the ERSTA (error status) and OPSTA
(operating status) parameters.
As a rule, all data points can be parameterized to start TSK253 in the case of EMC
changes. For this purpose, two parameters must be set in the respective points:
– OSV=0, i.e., the point must be "in operation" (normally true).
– EVE=1, i.e., the points must be able to start TSK 253.
In reality, only points that are to trigger event-dependent reactions are set to EVE=1.
Reaction task TSK253 is to be started if there are events in point addresses $010 and
$022. For this purpose, EVE=1 must be set in the point addresses, and the following
three program lines must be entered in reaction task TSK253:
TSK253
10 A:=EVADR
100 IF A=$010.ADR THEN RUN 101
110 IF A=$022.ADR THEN RUN 122
Line Meaning
10
Function EVADR is assigned to variable A. EVADR supplies the current point
address of the event.
100
If variable A contains point address $010.ADR, task 101 is started as a
reaction. If the event is not caused by $010.ADR, variable A contains the
point address of another point with OSV=0 and EVE=1 (z.B.$022.ADR).
110
If variable A contains point address $022.ADR, task 122 is started as a
reaction.
Please note the following for the above example:
– A start of tasks 101 or 122 is programmed as the reaction. Programming with all
available COLBAS commands is possible also.
– In order to ensure fast event processing, the command sequences in TSK253 must
be as short as possible. Actual reaction processing is to be defined externally in
tasks 1 to 199. In the example, reaction task TSK253 is started for an event of point
address $010 followed by TSK 101. This task contains the reactions that must first
be executed.
TSK 252 is used for events requiring an internal comparison such as feedback not
available, limit value exceeded, sensor break, etc..
For TSK 252 to be started, two parameters must be set as follows in the event-
triggering data point:
– OSV=0 (normally true).
– PRIO>0
If error state ERSTA, for example, changes from normal state ERSTA=0 to a fault state
ERSTA>0, reaction task TSK 252 is started.
Here also, the actual reaction processing is to be programmed externally, i.e., in tasks
1 to 199.
For further information on this topic, refer to "VISONIK system basics", topic 3,
"COLBAS tasks and BPS text catalogs“.
Two reaction tasks
Reaction task TSK 253
Example for TSK 253
Notes
Reaction task TSK 252
Additional informatio
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 2002 Siemens Building Technologies Ltd.