Ondt On Delay Timer Function Block - Honeywell HC900 Reference Manual

ONDT On Delay Timer Function Block

Description
The ONDT label stands for the On Delay Timer .
This block is part of the Fast Logic and Counters/Timers categories.
Function
Provides an ON state logic output delayed by a user specified delay time after an OFF to ON transition of
the RUN input.
An ON to OFF transition of the RUN input before the delay time has elapsed causes the timer to reset.
Transitions from OFF to ON of the input are not delayed.
If RUN is OFF, then OUT = OFF
•
If previous RUN input is OFF and RUN is ON, then TIMER = DELAY, else if timer is not zero, then
•
TIMER = TIMER -1.
If RUN is ON and TIMER is 0, then OUT = ON (delay time has timed out).
•
Timing Diagram
Input
RUN = Logic Input
Output
OUT = Logic Output
Revision 11
2/07
1
Run Input
0
1
Output
0
HC900 Hybrid Control Designer Function Block Reference Guide
ONDT On Delay Timer Function Block
On Delay
Function Blocks
225