DFM-6301 Models
Program Output
24
Relay Operation Details
Overview
The relay capabilities of the meter expand its usefulness beyond simple indication
to provide users with alarm and control functions. These capabilities include front
panel alarm status LEDs as well as 2 optional internal relays. Typical applications
include high or low flow alarms and basic batch control. There are four basic ways
the relays can be used:
1.
High or Low Alarms with Latching or Non-Latching Relays
2.
Simple On/Off Control with 100% Adjustable Deadband
3.
Sampling (Based on Time)
4.
Alternation Control for up to 8 relays
Relays Auto Initialization
When power is applied to the meter, the front panel LEDs and alarm relays will
reflect the state of the input to the meter. The following table indicates how the
alarm LEDs and relays will react on power-up based on the set and reset points:
Alarm #
HI or LO
Alarm
Set
Point
Reset
Point
Power-Up
Reading
Relay &
LED
1
HI
1000
500
499
Off
2
LO
700
900
499
On
3
LO
250
400
499
Off
4
HI
450
200
499
On
Fail-Safe Operation
The following table indicates how the relays behave based on the fail-safe
selection for each relay:
Fail-Safe
Selection
Non-Alarm State
Alarm State
Power Failure
NO
NC
NO
NC
Off
Open
Closed
Closed
Open
Relays go to
non-alarm state
On
Closed
Open
Open
Closed
Relays go to
alarm state
Note: NO = Normally Open, NC = Normally Closed. This refers to the condition of
the relay contacts when the power to the meter is off.
