Teledyne LGA-3500 - Laser Gas Analysis system - Manual (Page 40)

Operation Model 3500
Teledyne Analytical Instruments 26
system the self test ends and the system automatically enters normal
mode. In the normal mode, the LCD displays system information.
Figure 4.4: Self Testing Screen
4.2.2 Normal Mode
In the normal mode, the system performs gas concentration
measurement and monitoring. There are two different working states
within the normal mode:
Normal working status: In this state, the system is measuring
normally. The LCD shows the measured gas concentration value and
other system information; “Normal” is shown on the status bar. The
analog output port (4-20mA) sends out the corresponding measured
value.
Warning working status: When the system finds that the system
external input parameters (mainly the pressure and temperature of the
gas under test) are abnormal or the optical transmittance is too low, it
automatically switches to warning working status. In this status, the
front panel of the LCD shows the corresponding warning signal (Alarm
code on the status bar, and warning symbol
in MainMenu in
graphics mode). The system computes the gas concentration value using
default values for input parameters and sends out 4-20mA output
CAUTION: SCREEN DISPLAY OF THE MEASURED
CONCENTRATION MAY BE HIGHLY INACCURATE IN
THIS MODE.