Ofdt Function Block - Honeywell UMC800 Reference Manual

Function Blocks

2.44 OFDT Function Block

Description
The OFDT label stands for the Off Delay Timer. This block is part of the Fast Logic and Counters/Timers
categories. It looks like this graphically on the Control Builder.
Function
Provides an OFF state logic output delayed by a user specified delay time after an On to OFF transition of
the RESET input.
An OFF to ON transition of the RESET input before the delay time has elapsed causes the timer to reset.
Transitions from OFF to ON of the input are not delayed.
•
IF RESET is ON, then OUT = ON
•
If previous RESET input is ON and RESET is OFF, then TIMER = DELAY,
•
If RESET is OFF and TIMER is not 0, then time = TIMER -1
•
If RESET is OFF and TIMER is 0, then OUT = OFF (delay time is reset).
Timing Diagram
Rst Input
Output
Input
RST = Logic Input
Output
OUT = Logic Output
Block Properties
Double click on the function block to access the
function block properties dialog box.
Block Order (Read Only)
You can change the assigned execution order
number by selecting "Execution Order" in the
"Configure" menu and arrange the order to suit
your control strategy.
Configuration Parameters
You must configure the OFDT function Block
parameters to the desired value or selection that
matches your operating requirements.
Table 2-33 describes the parameters and the
value or selection.
116
1
0
1
Off Delay
0
Function Block Reference Guide
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