Model PD6000 Analog Input Process Meter Instruction Manual
Latching Relay (
Lt-Clr
)
Manual reset only after alarm condition has cleared
Condition
LED
Relay
Normal Off
Off
Alarm On
On
Ack (No effect)
On
On
Normal On
On
Ack Off
Off
In this application, the meter is set up for manual reset only after the
signal passes the reset point (alarm condition has cleared). Acknowl-
edging the alarm while it is still present has no effect on either the LED
or the relay. When the alarm is acknowledged after it returns to the
normal state, the LED and the relay go off. Notice that the LED remains
on, even after the meter returns to the normal condition. This is be-
cause, for latching relays, the alarm LED reflects the status of the relay,
regardless of the alarm condition.
Acknowledging Relays
There are two ways to acknowledge relays programmed for manual
reset: via the programmable front panel function keys F1-F3 (Default:
F3 assigned to ACK) and remotely via a normally open pushbutton
wired across one of the digital inputs and the +5 V terminals on the digi-
tal I/O modules (Default: DI-4 assigned to ACK). When the ACK button
or the assigned digital input is closed, all relays programmed for manual
reset are acknowledged.
+5
I1
I2
I3
I4
O1
O2
O3
O4
G
DO 1-4
GND
ACK
PDA1044 Digital I/O Module
1
2
3
4
5
6
7
8
9
10
DI 1-4
Figure 17. Acknowledge Relays w/Function Key or Digital Input
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