TSI Instruments SUREFLOW 8635-M, Operation And Service Manual

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18
Pa
rt
Two
ALARM CONSTRAINTS (continued)
8. The display can only show one alarm message. Therefore, the controller has an alarm priority system, with the highest
priority alarm being displayed. If multiple alarms exist, the lower priority alarms will not display until after the highest
priority alarm has been eliminated. The alarm priority is as follows:
Pressure sensor - low alarm
Pressure sensor - high alarm
Flow station - minimum flow
Data error
9.
The low and high alarms are absolute values. The chart below shows how the values must be programmed in order to
operate correctly.
-0.2 inches H
2
O 0 +0.2 inches H
2
O
(maximum negative) (maximum positive)
High Low Zero Low High
Negative Negative Positive Positive
Alarm Alarm Alarm Alarm
The value of each set point or alarm is unimportant (except for small dead band) in graph above. It is important to
understand that the negative (positive) low alarm must be between zero (0) pressure and the negative (positive) high
alarm value.