FLUID COMPONENTS INTL CHAPTER 3 - OPERATION
Fail Safe Alarm Setting
These procedures set the second relay to detect component failure (fail-safe).
Low Flow Alarm Settings
For the low flow fail safe setup the following jumpers are to be installed: J18, J20, J23, J24, J27.
WHEN ALARM 1 DETECTS LOW
FLOW THERE IS A POSSIBLE OPEN
5.0
ACTIVE RTD OR SHORTED
4.5
DE-ENERGIZED
REFERENCE RTD
4.0
ALARM 1 SET POINT
WHEN ALARM 2 DETECTS OVER
ENERGIZED
3.5
RANGE FLOW, THERE IS A POSSIBLE
3.0
HEATER FAILURE,
SIGNAL
SHORTED ACTIVE RTD OR
2.5
OUTPUT
OPEN REFERENCE RTD
2.0
A POWER FAILURE IS DETECTED IF
1.5
BOTH RELAYS ARE DE-ENERGIZED
1.0
ENERGIZED
0.5
ALARM 2 SET POINT
0
DE-ENERGIZED
0 10 20 30 40 50 60
AIR FLOW RATE
C00534-1
Figure 3-5. Low Flow Fail Safe Alarm
The following information is assumed:
Relay is de-energized in the ALARM condition.
Alarm 1 set point is adjusted for desired low flow alarm velocity or signal.
Alarm 2 set point is adjusted slightly below minimum signal output (over range flow).
High Flow Alarm Settings
For the high flow fail safe setup the following jumpers are to be installed: J18, J20, J23, J25, J26.
DE-ENERGIZED
ALARM 2 SET POINT
WHEN ALARM 1 DETECTS HIGH
ENERGIZED
FLOW, THERE IS A POSSIBLE
5.0
HEATER FAILURE,
4.5
SHORTED ACTIVE RTD OR
OPEN REFERENCE RTD
SIGNAL
4.0
OUTPUT
3.5
WHEN ALARM 2 DETECTS AN
UNDER RANGE FLOW, THERE IS A
3.0
POSSIBLE OPEN ACTIVE RTD OR
2.5
SHORTED REFERENCE RTD
ENERGIZED
2.0
A POWER FAILURE IS DETECTED IF
1.5
ALARM 1 SET POINT
BOTH RELAYS ARE DE-ENERGIZED
1.0
DE-ENERGIZED
0.5
0
0 10 20 30 40 50 60
AIR FLOW RATE
C00535-1
Figure 3-6. High Flow Fail Safe Alarm
The following information is assumed:
Relay is de-energized in the ALARM condition.
Alarm 1 set point is adjusted for desired high flow alarm velocity or signal.
Alarm 2 set point is adjusted above maximum signal output (under range flow not to exceed 7.0 volts).
FLTÔ Series FlexSwitchÔ 3 - 20 Doc. No. 06EN003246 Rev. B
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