MA-037 - CB Watch 3 Operating Manual
v7.0 - May 2020
Page 45 of 118
Figure 60
–
Equivalent density lines and liquefaction curve
Gas sensors used
Two types of gas sensors are used depending on the options selected. Both output a digital
signal (rather than an analogue signal) and measure the following parameters:
•
Gas pr gas temperature
•
Gas pr gas tempe moisture level in gas
The sensor serial number is displayed in the HMI (see figure below).
Sensor related alarms
In case the system loses communication with the gas sensor, it retries communication up to
5 times. If there is still no answer from the digital sensor, then the sensor power supply is
turned off and on again to reset the communication protocol. A counter is kept of the
number of “no answer”. The reset procedure may be repeated 3 times before the sensor is
declared faulty and t
he “Sensor absence” alarm is raised.
HMI: Measurements/Sensors
Figure 61
–
Gas sensor information
Whenever the sensor answers again
, the “no answer” counter is reset
automatically.
In case data is being received from the sensor but more than 50% of the digital data values
received are incorrect or corrupted, then the “Sensor data validity” alarm is raised.
