Emerson Rosemount 3490 Series Reference Manual page 97

Reference Manual
00809-0100-4841
Table 4-9: Relay Modes
Relay mode
Digital input 1+2
Off
Set Point
Alarm
Hi or Lo Alarm
Totalizer
Totalizer 1
Totalizer 2
Fault
Custom
PV limits
On
Auxiliary functions for relay modes
Relay modes automatically enable and disable special control functions, special alarms
and pumped volume totalizing as shown in
Emerson.com/Rosemount
(continued)
Purpose of relay mode
Relay is energized while Digital Input 1 (IN1) and 2 (IN2)
are both active.
Relay is always de-energized.
On/Off Point Control using PV (D800).
Relay is allocated to alarm indication duty.
High alarm limit (using On/Off Point Control):
• The On Point must be greater than the Off Point.
• Relay energizes when the PV (D800) is greater than the
On Point.
• Relay de-energizes when the PV (D800) is less than the
Off Point.
Low alarm limit (using On/Off Point Control):
• The On Point must be less than the Off Point.
• Relay energizes when the PV (D800) is less than the Off
Point.
• Relay de-energizes when the PV (D800) is greater than
the On Point.
An "A" is shown by the RL1 icon status (on the Full PV
Display) when there is a high or low alarm. (The section
Set-up alarms is not applicable).
(Rosemount 3491 only) Relay outputs totalizer pulses.
(Rosemount 3492/3493 only) Relay outputs totalizer 1
pulses.
(Rosemount 3492/3493 only) Relay outputs totalizer 2
pulses.
Indicate fault condition by de-energizing relay.
Custom relay operation.
Relay energizes while control unit PV value (D800) is
within on/off point limits.
Relay is always energized.
Table 4-10 and Table 4-11.
Getting started
January 2021
Auxiliary
functions
Yes
No
Yes
Yes
Yes
No
No
No
No
No
Yes
No
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