Vaisala FS11 - Alarm Messages; Contamination Compensation

Chapter 5 _________________________________________________________ Theory of Operation
VAISALA _______________________________________________________________________ 117
The heater status indicates whether the automatic heater control circuitry
has been turned on. When the automatic heater control circuitry is on, it
will automatically switch the heater on and off trying to keep the
temperature within the acceptable range.
An asterisk (*) in front of the heater status (ON/OFF) indicates that the
heater is currently heating.
Alarm Messages
This section describes the different alarm message types of the FS11
sensor.
Table 19 Error Messages
ERRORS
Reasons
SENSOR NOT RESPONDING
Measurement unit FSM102 or LM21 not
responding
MEMORY ERROR
FLASH memory checksum error,
configuration not valid
Table 20 Alarm Messages
ALARMS
Reasons
TRANSMITTER FAILURE
Transmitter not responding
LED FAILURE
Transmitter LED intensity too low
RECEIVER FAILURE
Receiver data invalid or receiver not
responding
POWER SUPPLY
One of the power supply voltages out of
the valid range
BACKSCATTER HIGH
Backscatter signal level increased, some
disturbance in the light path
RECEIVER SATURATED
Ambient light level too high on the receiver,
caused by, for example, sunbeams
reflecting from a reflecting surface
SCATTER SIGNAL
SATURATED
There is an obstacle in the measurement
volume that causes excessive scattering.
SIGNAL OFFSET DRIFTED
Offset has drifted more than ±5 LSB from
zero, caused by other disturbing visibility
sensors nearby or other interference
problems.
TEMPERATURE SENSOR
FAILURE
The surface temperature sensor is
disconnected or has failed.