Brooks Instrument Ar-Mite MT3750 Manuel D'installation Et D'opération page 35

Installation and Operation Manual
X-VA-MT3750C-eng
Part Number: 541B063AAG
October, 2013
C.Two jumper configurations allow simultaneous use of both the high and
low alarm circuits. In the first of these configurations, an alarm is
always active. If the flow rate is under the set point, the low alarm circuit
is closed. If the flow exceeds the set point, the low alarm circuit opens
and the hi alarm circuit closes. There is hysteresis associated with reed
switches, so the flow rates at which the alarm switches between HI and
LO will be slightly different depending on whether the flow rate is
increasing or decreasing.
The second "Dual" alarm option allows separately adjusting the set
points for low flow alarm and high flow alarm within a limited range of
the maximum flow rate of the meter.
The dual setpoint alarm is set in the same manner as described in
Section 3-4. Simply use two ohmmeters to observe the behavior of both
circuits.
Table 3-1 Interior Label MT 3750 Ar-Mite Alarm.
Alarm Programming Table
Alarm
Flow
Range
High, 60-100%
High, 40-75%
High, 0-40%
Low, 55-100%
Low, 40-75%
Low, 0-40%
Dual:
High, 40-75%
Low, 30-60%
Dual:
High, 40-75%
Low, 10-45%
(1) These ranges for reference only.
(2) Final sensor position may be slightly outside of these ranges.
Section 3 Operation
®
Brooks Ar-Mite
Jumper Adjust Upper
Positions Sensor in
Region (2)
J-2,5,7 B
J-1,4,6 A
J-1,3,5 B
J-2,3,7 B
J-1,4,6 A
J-1,5,7 B
J-1,4,6 A
J-1,6,8 A
(High Set)
TM
MT3750C
Lower
Sensor
Position
Bottom
of Slot
Bottom
of Slot
Bottom
of Slot
Bottom
of Slot
Bottom
of Slot
Bottom
of Slot
Bottom
of Slot
Region B
(Low Set)
3-3