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Latching relay ( lt-clr ), Acknowledging relays, Pda1044 digital i/o module – Precision Digital PD6100 User Manual

Page 62

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Model PD6100 Strain Gauge/Load Cell Meter Instruction Manual

62

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).
Acknowledging 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
because, 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:

1. Via the programmable front panel function keys F1-F3

(Assignable via the User menu inside the Advanced Features
menu.

2. Remotely via a normally open pushbutton wired across one of

the digital inputs and the +5 V terminals on the digital I/O
modules, or using the F4 digital input (factory default setting),
which is triggered with a contact closure to COM, or with an
active low signal (see page 26).

When the ACK button or the assigned digital input is closed, all relays
programmed for manual reset are acknowledged.
Note: The function key and digital input assignment is changed in the
Advanced – User menu.

Figure 23. Acknowledge Relays with Digital Input

+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

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