Topic: DMD0174
OFFDTMR - OFF Delay Timer
The Off Delay Timer (OFFDTMR) has one ladder logic input leg which enables and resets the Timer. This type of timer is the opposite of the On Delay Timer in that it "delays turning off" by the Off Delay Time. The Off Delay Timer times down.
If the input logic is ON, the Output will be latched ON. Then when the
input logic transitions OFF, the Timer will begin timing. Once the Off
Delay Time value is reached, the Timer will reset, setting
Refer to the following timing diagram:
Parameters:
Note: Use the F9 key (Element Browser) or Down-Arrow key (Auto-Complete) at any time to see a complete list of the memory locations that are valid in the current field of the instruction.
Timer Struct - specifies a unique Timer structure that will be used by this instruction.
Off Delay Time - is the amount
of time after which you want the specified Output to go OFF. The Off Delay
Timer has a resolution of 1 millisecond. The maximum value for a Timer
Preset is 2,147,483,647 milliseconds. The Off Delay Time value can be
specified in one of two ways:
Constant - specified using the Time format (HH : MM : SS : mmm).
The maximum Time value in this form is 569
hours, 31 minutes, 23 seconds, and 647 milliseconds. If needed, the value
entered for the Off Delay Time will be normalized to its standard value.
For example, if you entered a value of
When editing the Constant Preset value, the following keystrokes are available
to make entering the value easier and faster:
h - takes you to the Hours field
m - takes you to the Minutes field
s - takes you to the Seconds field
mm - takes you to the Milliseconds field
Variable - designates a location that contains the total number of milliseconds desired for the Off Delay Time. This can be any readable numeric location.
Output - designates the bit location that will be turned OFF after the Off Delay Time has expired. This can be any writable bit location.
Status Display:
The yellow triangle in the upper left corner indicates this is a Multi-Scan instruction.
The Off Delay Timer instruction provides several status values that
can be used elsewhere in your ladder program. Their values are updated
each time the OFFDTMR instruction is processed. The syntax for using them
is <timer struct>.<flag name>, for example, T7.Acc.
.Acc (Accumulator) - a 32-bit signed value that represents the time remaining before the preset reaches 0
.Done - is ON any time the Off Delay Timer is enabled and it's accumulator value (.Acc) is 0
- .Reset - is ON if the input logic is ON, or if the Timer is being reset by an RSTT instruction
.Zero - is ON any time the Off Delay Timer's accumulator value (.Acc) is 0
.Timing - is ON if the Off Delay Timer is enabled and the accumulator value (.Acc) is not 0
See Also:
OFFDTMR - On Delay Timer
Rung Example:
