Model PD655 Large Display Process Meter
Instruction Manual
74
Relay key legend for following tables
Key
Relay condition
On Tripped
Off Reset
Ack Acknowledged
The On and Off keys do not refer to the status of the relay’s coil, which depends
on the fail-safe mode selected.
Non-Latching Relay
Automatic reset only JP5(1-4 off)
Condition
LED
Relay
Normal Off
Off
Alarm On
On
Ack (No effect)
On
On
Normal Off
Off
In this application, the meter is set up for automatic reset and 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.
Non-Latching Relay
Aut manual reset at any time JP5(1-4 on)
Condition
LED
Relay
Normal Off
Off
Alarm On
On
Normal Off
Off
In this application, the meter is set up for aut manual reset at any time
and non-latching relay. The LED and the relay automatically reset when the
meter returned to the normal condition.
Aut manual reset at any time JP5(1-4 on)
Condition
LED
Relay
Normal Off
Off
Alarm On
On
Ack
On
Off
Normal Off
Off
In this application, the meter is also set up for aut manual reset at any
time. But this time, an operator acknowledges the alarm manually while it still
exists. This causes the relay to reset, but the LED stays On until the meter
returns to the normal condition. (Remember, for non-latching relays, the LED is
always Off during normal condition and always On during alarm condition,
regardless of the state of the relay).
