DPM-100 Digital Panel Meter Modbus
®
Display
Instruction Manual
44
Non-Latching Relay (
Auto
)
In this application, the scanner is set up for automatic
reset (non-latching relay). Acknowledging the alarm
while it is still present has no effect on either the LED
or the relay. When the alarm finally goes away, the
relay automatically resets and the LED also goes off.
Automatic reset only
Condition
LED
Relay
Normal
Off
Off
Alarm
On
On
Ack (No effect) On
On
Normal
Off
Off
Non-Latching Relay with Manual
Reset (
A-nman
)
In this application, the scanner is set up for automatic
and manual reset at any time (non-latching relay).
The LED and the relay automatically reset when the
scanner returns to the normal condition.
In addition, the relay can be manually reset while the
alarm condition still exists, but the LED will stay on
until the scanner returns to the normal condition.
Aut manual reset at any time
Condition
LED
Relay
Normal
Off
Off
Alarm
On
On
Normal
Off
Off
Next Alarm
On
On
Ack
On
Off
Normal
Off
Off
Latching Relay (
LatcH
)
In this application, the scanner is set up for manual
reset at any time. Acknowledging the alarm even if
the alarm condition is still present resets the relay and
turns off the LED.
Manual reset any time
Condition
LED
Relay
Normal
Off
Off
Alarm
On
On
Ack
Off
Off
Latching Relay with Clear (
Lt-Clr
)
In this application, the scanner 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 scanner 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.
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
Acknowledging Relays
There are three ways to acknowledge relays
programmed for manual reset:
1. Via the programmable front panel function keys
F1-F3 (Example: F3 assigned to ACK).
2. Remotely via a normally open pushbutton wired
to the F4 terminal at the rear of the instrument.
3. One of the digital inputs and the +5 V terminals
on the digital I/O expansion module.
When the ACK button or the assigned digital input is
closed, all relays programmed for manual reset are
acknowledged.
