Operation
Fault Codes & Their Remedies (continued)
F4 = Sensor Reference Bead Error
This fault may occur as a result of one of the
following:
l excessive negative drift
l an open sensor reference bead
l the sensor BLACK wire is disconnected
ACTION - Attempt to recalibrate the unit. If
this is unsuccessful make sure that the
BLACK sensor wire is connected to the termi-
nal block. If both of these actions do not cure
the fault condition, then replace sensor.
F5 = Sensor Active Bead Error
This fault occurs if the sensor active bead be-
comes open circuited or, if the sensor WHITE
or the sensor RED lead becomes disconnected.
ACTION - Check the WHITE and RED wires
or replace the sensor as appropriate.
F6 = Low Supply Voltage
This fault occurs if the supply voltage drops
below +17VDC approximately. ACTION -
Ensure that the supply voltage is at least
+20VDC at the Model S104.
Correcting this Fault will initiate the Start-Up
Mode.
NOTE: With long supply leads, a consider-
able voltage drop may occur due to the elec-
trical resistance of the leads.
The maximum cable resistance which the
Model S104 can tolerate is dependent on the
supply voltage. A maximum of 20 ohms per
conductor (40 ohms loop) at +24VDC mini-
mum, or a maximum of 10 ohms per conduc-
tor (20 ohms loop) at +20VDC minimum.
F7 = EEPROM Verification Failure
This fault occurs during calibration when an
attempt to verify the calibration parameters
just written to the non-volatile memory fails.
The usual cause of this is electrical interfer-
ence corrupting the data (although on rare oc-
casions it may indicate a problem within the
electronics module). ACTION - Place the
magnet over the GMI Logo and the unit will
attempt another EEPROM write and verify.
F8 = Negative Zero Drift
If the zero baseline of the sensor drifts 10% of
full scale below zero for more than 20 seconds
this fault will occur. ACTION - A routine re-
calibration will be required.
F9 = Calibration Check Period Exceeded
If the Model S104 is left in the Test Gas Mode
for more than six minutes without a Test Gas
being applied, this fault will occur. ACTION
- Place the magnet over the General Monitors
Logo to return the unit to normal operation.
NOTE: Anytime a sensor is replaced, the unit
should be disconnected from all alarms, as the
unit may go upscale upon power-up.
NOTE:
Model S104 without display has
limited fault diagnostic capabilities. It can
sense calibration, sensor and low voltage
faults. See figure 17 for LED sequences.
16
GENERAL MONITORS
Model S104
To Next Page
