User Manual

CM2U8567E / 04.1999 VISONIK DCS Functions and System Messages VVS18 Siemens Building Technologies
2-246 Reactions Landis & Staefa Division
2.27.2 Special Features of Digital Output Points
2.27.2.1 Change Setpoint to the Last Valid Value
When the reaction is triggered, the most recently valid setpoint (RDO/RFL) of a switch
command point is restored (e.g. after a power failure). The parameter FBX of the DO
point must at least have the value NO.
This type of reaction is especially efficient when it is used in a step reaction chain.
This results in:
–
Faster execution
–
Special message indicating the current set state, the SRR flag and the SRR entry
number, which allows the user to monitor the progression of the reaction chain via the
report.
–
No waiting on programmed SRR delays when no DO output is needed (FB=DO
RVAL).
–
Any active plant suppression on the reaction address is lifted immediately after the
reaction.
Procedure:
Reaction =(UA,TA): $100'041
Parameter =DO :
Set Digital Output: Priority=0 =Off : ?
Set Digital Output: Priority=0 =(Off,On), (LSPV,SAME,INV,.): LSPV
1.Further Address =. :
Message Mask =MSGDEV : 2
2.27.2.2 Change of Parameter to the SAME as any Main Value
When the reaction is triggered, the parameter value of the reaction address is set
the
SAME
as the main value of any chosen point (so-called function address
"FNT/Address =").
Reaction =(UA,TA): $100'041
Parameter =DO :
Set Digital Output: Priority=0 =Off : ?
Set Digital Output: Priority=0 =(Off,On), (LSPV,SAME,INV,.): SAME
FNT /Address =$d100'040: $F10
1.Further Address =. :
Message Mask =MSGDEV : 2
The following must be noted:
–
The parameter values of both the reaction address and the function address must
have the same format.
–
If the parameter of a function address is an analogue value (e.g. AI) it is first rounded
to an integer before it is assigned to a digital parameter value of a reaction address
(e.g. DO, MSGP, etc.).
The VISONIK DCS sets a switch command to the SAME as a measurement of AI=1.64
Deg.C, i.e. DO=1.64 resulting in DO=2.
–
If the parameter value of the function address is outside the limits of the reaction
address's parameter value, the VISONIK DCS automatically sets the parameter of the
reaction address to its upper or lower limit as appropriate.
Example