User Manual

CM2U8567E / 04.1999 VISONIK DCS Functions and System Messages VVS18 Siemens Building Technologies
2-136 Function DRR Landis & Staefa Division
2.13.7 Special Features
After every Date Reaction, VISONIK automatically calculates the time of the next
Reaction based on the period as defined in the relative Reaction entry and updates the
Reaction Register. Such a calculation can be seen in any listing of a Date Reaction
entry where it is printed in brackets alongside the specified data, i.e. when the next Date
Reaction will take place or how often the Reaction will be executed.
If for some reason the system time is reset then the time of the next execution is applied
to the DRR entries.
If the system date/time is put forward (e.g. after a system HALT and advancing the
time), VISONIK updates all those Date Reactions which should have been executed
during this skipped time. To avoid unnecessary switching, the plant equipment is
brought to positions which agree with the set status in the DRR entries.
An updated Date Reaction is marked by an exclamation sign in the relative message
line:
!DRR SC 16:40:09 a01'b2'SC SC =OFF--->ON
RVAL=ON(1)
To calculate the next Reaction the period as defined in the Reaction Register is still
valid. If a period is longer than the skipped interval it is reduced, but the Reaction will
always be carried out at the time calculated.
The update logic does not work in the following circumstances:
–
On system start with BOO,Z
–
On generating/changing the system time/date (in Function DATE), and the user has
set "Update Date & Time Reactions =NO".
–
In Macro Reactions (MC) if there has been a break in system time of more than 2
hours.
On changeover from summertime to wintertime VISONIK automatically makes a double
pass through the hours between 02:00 a.m. and 03:00 a.m. All Date Reactions which
fall within this time span are carried out during the first pass. A Date Reaction whose
interval is less than 1 hour will only be executed a second time if the interval is a whole
fraction of 60 minutes
(1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 minutes).
On changeover from wintertime to summertime VISONIK automatically advances the
time from 02:00 a.m. to 03:00 a.m. All Date Reactions which should have taken place in
this skipped time will be executed, once only, at 03:00 a.m. (corresponds to putting
forward the system Time/Date).
Next Date Reaction
System Time Reset
Update Logic
Summer/Wintertime
Changeover
Changeover
Winter/Summertime