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Reference Manual
300530EN, Rev BA
September 2012
C-9
Rosemount 2410
Appendix C. Advanced Configuration
Relay Zones
You can use one or two set points for relays connected to the Rosemount
2410 Tank Hub. Consequently, there are two or three zones in which different
relay states can be specified. For each zone you can set any of the three
available relay states Normal, Alarm or Toggle.
For each set point you can specify a hysteresis zone preventing the relay from
switching back to its previous state as long as the source variable is changed
only small amounts around a certain set point. The principle of relay set points
and hysteresis zones is shown in the figure below. Note that in this example
only two states are used.
Figure C-5. Relay zones
1. The source signal passes set point 1, and the relay state changes
according to the definition for Zone 1.
2. When the source signal returns into Zone 2, it does not change to the
Zone 2 state until it has passed the hysteresis zone.
3. The source signal passes set point 2, and the relay state is changed
according to the definition for Zone 3.
4. The relay switches back to the Zone 2 relay state when the source signal
has passed set point 2 and the associated hysteresis value.
Relay state
Time
ZONE 1
ZONE 2
ZONE 3
Source signal
1
2
3
4
Relay State
Zone 1
Relay State
Zone 2
Relay State Zone 3
Relay State Zone 2
Hysteresis zone
Hysteresis zone
Set Point 2
Set Point 1