TSI Instruments PRESSURA 8630-SM - Page 40

Part Two
34
Symptom
Possible Cause
Corrective Action
DIM displays
opposite
pressure signal.
Sensor direction is
incorrect.
Pressure sensor must have DIP switch correctly set for
proper sign display. Verify DIP switch 4 is ON when
sensor is mounted in isolation room (controlled space),
and OFF when mounted in reference space (see Figure
9).
Sensor does not
calibrate.
Incorrect pressure
sensor address.
Primary pressure sensor must have address of 1.
Second sensor must have address of 2. Check pressure
sensor DIP switches 5 & 6 and verify address is correct
(7 to 12 must be OFF).
Figure 9: Pressure sensor DIP switch
Positive/
negative/ neutral
key switch
doesn’t work.
Incorrect wiring.
Room mode is
incorrect.
Defective switch /
defective DIM.
Verify wiring is correct between key switch and DIM.
Go into CONFIGURE menu, ROOM MODE item. Verify
ROOM MODE is in key switch position.
Verify ROOM MODE is in key switch position. Go into
DIAGNOSTICS menu, KEY INPUT item. Display should
read negative in negative position, positive in positive
position, and no isolation in neutral position. If display
changes correctly, switch and switch input is good. If
display does not change:
Disconnect key switch wires from DIM pins 11 and 12.
Measure the resistance of the switch:
Negative position should be open (infinite).
Neutral position should read approximately 273 K
Ohms.
Positive position should be closed (short).
If room mode is correct and resistance check is good,
DIM key input is probably defective. Replace DIM.