Vaisala FS11 - Page 5

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VAISALA _________________________________________________________________________ 3
System Configuration .................................................... 90
Default Factory Settings .............................................. 90
Optional External Sensors .......................................... 91
LM21 Background Luminance Sensor ............... 91
Day/Night Sensor ..................................................... 91
Simulated Test Messages ............................................. 92
Fixed Test Messages ................................................... 92
Manual Simulation Message ...................................... 93
Operating LM21 through Maintenance Port .......... 95
Serial Communication Settings ............................ 95
Serial Transmission RS-232 ................................. 95
Entering and Exiting Command Mode .................... 96
OPEN Command ...................................................... 96
CLOSE Command ................................................... 96
Available Commands ................................................... 97
Parameter Configuration ............................................. 99
Default Settings for FS11 Use ............................ 100
LM21 Standard Initialization........................... 100
CHAPTER 5
THEORY OF OPERATION ................................................................ 101
Hardware Description ................................................... 103
Measurement Unit FSM102 ..................................... 103
Transmitter Unit FST102 ...................................... 103
Receiver Unit FSR102 .......................................... 105
Controller Board FSC102..................................... 107
Interface Unit FSI102 ................................................. 107
Communication Controller Board FSC202 ..... 108
AC (Mains) Power Supply .................................... 108
Battery Backup ........................................................ 109
Frangible Mast .............................................................. 109
Software Description .................................................... 110
Measuring Sequence ................................................. 110
Visibility Measuring Principle ................................... 110
Calculations ................................................................... 111
Internal Monitoring ........................................................ 111
FS11 Status Messages.............................................. 111
Event Messages ..................................................... 112
Alarm Messages ..................................................... 117
Optical Contamination and Blocking
Monitoring ...................................................................... 118
Contamination Compensation ............................ 119
Signal Monitoring ......................................................... 120
Transmitter Intensity Stability ................................... 120
Heaters Operation ....................................................... 121
Power Supplies ............................................................ 121
Analog Interfaces ......................................................... 122