Table of Contents

Time scheduler bool, basic

Block name

T17_BOOLEAN_SCHEDULER_BASE

ST call

PROGRAM TEST_T17_BASE
  VAR 
        FB : LIB.HVAC.V1_0.T17_BOOLEAN_SCHEDULER_BASE := (TPGVALUE := [(STARTTIME := 0, STATE := FALSE),
        (STARTTIME := 210, STATE := TRUE),
      (STARTTIME := 420, STATE := FALSE)],
        DT1:DT;
     BOOL1:BOOL;
 END_VAR
 DT1:=getlocaltime();
    FB(CURRENTTIME:=DT1, OUT=>BOOL1);
END_PROGRAM

Library

LIB\HVAC

Version

V1.0

Description

Time scheduler basic is a source of a binary signal which changes according to a weekly schedule with maximum 42 events (changes of state). This scheduler doesn't  support exceptions. Exceptions are implemented in T17_BOOLEAN_SCHEDULER.

The output value is recalculated at 30-second intervals.

Inputs

Input TypeDescription
CURRENTTIME DT Date and time in case that other date and time than system date and time shall be used
DEFAULTVALUEBOOLOutput value if en=false

Outputs

OUTBOOLCurrent time scheduler state

Description of internal structures

DescriptionImportance
STATE Current state of the time program
STARTTIME Minutes from the beginning of the day

Function

The time scheduler basic compares current date and time with the definition table and sends the actual state to the output. The output is either true or false. The time scheduler can be edited from IDE or HMI - LCD display, web interface, touchscreen, SCADA or another client).

Application example

Time scheduler is used to enable plant operation according to the operating hours plan, for night depressions, etc. (Use T19_INT_SCHEDULER for multistate output, and T18_REAL_SCHEDULER for direct output of analogue values.)

The image illustrated switching between day and night heating curve. At the daytime the scheduler output is on TRUE, at the nighttime it is on FALSE.

In the editor, the scheduler plan is set up to be TRUE from 6:00 to 22:00, and FALSE otherwise: