Timer And Counter Functions Off-Delay Timer - GE VersaMax PLC User Manual

DO_DWL
DWELL
DWELL
CONST
+00005
Instruction Set Reference
For public disclosure
The contact of coil DWELL keeps coil DWELL energized (when contact DO_DWL is
released), and also starts the timer TMRID. When TMRID reaches its preset value of
one-half second, coil REL energizes, interrupting the latched-on condition of coil
DWELL. The contact DWELL interrupts power flow to TMRID, resetting its current
value and de-energizing coil REL. The circuit is then ready for another momentary
activation of contact DO_DWL.
REL
TMR
0.15
PV
TMRID

10.9.3 Timer and Counter Functions Off-Delay Timer

The Off-Delay Timer increments while power flow is off and resets to zero when power
flow is on. Time may be counted in tenths (0.1), hundredths (0.01), or thousandths (0.001)
of a second. Range is 0 to +32,767 time units. The state of this timer is retentive on power
failure; no automatic initialization occurs at power-up.
Enable
OFDT
1.00s
Preset Value
PV
Address-3 words
When the Off-Delay Timer first receives power flow, it passes power to the right, and the
Current Value (CV) is set to zero. The function uses word 1 [register] as its CV storage
location. The output remains on as long as the function receives power flow. If the
function stops receiving power flow from the left, it continues to pass power to the right,
and the timer starts accumulating time in the Current Value. The Off-Delay Timer does
not pass power flow if the Preset Value is zero or negative.
If multiple occurrences of the same timer with the same reference address are enabled
during a CPU sweep, the Current Values of the timers will be the same.
updated to reflect the elapsed time since the timer was turned off. When the Current Value
(CV) is equal to the Preset Value (PV), the function stops passing power flow to the right
and the timer stops accumulating. When the function receives power flow again, the
current value resets to zero. When this timer is used in a program block that is not called
every sweep, it accumulates time between calls to the program block unless it is reset.
That means it functions like a timer in a program with a much slower sweep than the
timer in the main program block. For program blocks that are inactive for a long time, the
timer should be programmed to allow for this catch-up. For example, if a timer in a
program block is reset and the program block is inactive for four minutes, when the
program block is called, four minutes of time will have accumulated. This time is applied
to the timer when enabled unless the timer is first reset.
(Q)
Current Value
CV
DWELL
REL
GFK-1503E User Manual 189