Time scheduler real, basic
FB : LIB.HVAC.V1_0.T18_REAL_SCHEDULER_BASE := (TPGVALUE := [(STARTTIME := 0, STATE := 0),
(STARTTIME := 370, STATE := 1),
(STARTTIME := 650, STATE := 3),
(STARTTIME := 2070, STATE := 8)],
FB(CURRENTTIME:=DT1, OUT=> REAL1);
Time scheduler is a source of a real variable which value changes according to a weekly schedule with maximum 42 events (changes of state). This scheduler doesn't support exceptions. Exceptions are implemented in T18_REAL_SCHEDULER.
|CURRENTTIME||DT||Date and time in case that other date and time than system date and time shall be used|
|DEFAULTVALUE||REAL||Output value if en=false|
|OUT||REAL||Current time schedule state|
|STATE||Current state of the time program|
|STARTTIME||Minutes from the beginning of the day|
The time scheduler compares current date and time with the definition table and sends the actual state to the output. The output is a real value. The time scheduler can be edited from Idekit Studio or HMI - LCD display, web interface, touchscreen, SCADA or another client).
Time scheduler is used to specify variable setpoints in time directly. (Use T19_INT_SCHEDULER for multistate output, like switching between Comfort, Standby, and Off, and boolean scheduler to enable plant operation according to a time schedule.)
At the image below, T18 is used to generate a temperature setpoint for an air handling unit. A correction from a room unit (AHU1_TEMP_CORR) is added, and the result is brought to the air supply PI controller.
In the editor, the basic setpoint is set to 18 °C, and the operation hours setpoint is 21 °C: