PD8-6262 Explosion-Proof Dual Analog Input Flow Rate/Totalizer
Instruction Manual
42
Programming Set and Reset Points
High alarm indication: program set point above reset
point.
Low alarm indication: program set point below reset
point.
The deadband is determined by the difference
between set and reset points. Minimum deadband is
one display count. If the set and reset points are
programmed with the same value, the relay will reset
one count below the set point.
Note:
Changes are not saved until the reset point has been
accepted.
Setting Fail-Safe Operation
In fail-safe mode of operation, the relay coil is
energized when the process variable is within safe
limits and the relay coil is de-energized when the
alarm condition exists. The fail-safe operation is set
independently for each relay. Select
on
to enable or
select
off
to disable fail-safe operation.
Programming Time Delay
The
On
and
Off
time delays may be programmed for
each relay between 0 and 999.9 seconds. The relays
will transfer only after the condition has been
maintained for the corresponding time delay.
The
On
time delay is associated with the set point.
The
Off
time delay is associated with the reset point.
Relay Action for Loss of 4-20 mA
Input (Loop Break)
The loop break feature is associated with the 4-20 mA
input. Each relay may be programmed to go to one of
the following conditions when the totalizer detects the
loss of the input signal (i.e. < 0.005 mA):
1. Turn
On
(Go to alarm condition)
2. Turn
Off
(Go to non-alarm condition)
3. Ignore (Processed as a low signal condition)
Note:
This is not a true loop break condition; if the signal
drops below 0.005 mA, it is interpreted as a
“loop break” condition.
The following graph shows the loop break relay
operation for a high alarm relay.
