Vaisala FD12P - Manual (Page 139)

Chapter 7 ____________________________________________________________ Troubleshooting
VAISALA _______________________________________________________________________ 139
Message Typical Min/
Max Fault Description Action
TR.
BACKSCATTER
Control signal for
the transmitter
contamination.
Clean value. <-15 V
>14 V
'TRANS-
MITTER
ERROR' Decreasing value can be
caused as above (REC.
BACKSCATTER)
LEDI
Actuating signal for
the LED control
(transmitter). 0 V ...
6.5 V -8 V/
+7 V >+7 V
<-8 V Changes in the voltage
can be caused by
-aging of the LED
(voltage decreases)
-rising temperature
(voltage decreases)
-changes depending on
ambient temperature
(temperature control is
possibly not working).
If the voltage is between -
3 V ... -8 V, the control
loop is operating properly
but the IR LED may
change for the worse in
the near future. Change the
transmitter.
TE
Ambient
temperature. -40 °C ...
+50 °C
<-60 °C
>+50 °C at any
rate
Sensor disconnected.
Sensor or cable is short
circuit.
Check X14
connection on CPU
board.
Check temperature
sensor cable on
CPU board.
SIGNAL
Frequency of the
transmission signal
between
transducer and
CPU (Hz) is
inversely
proportional to
visibility.
Freq. Corr.
Visibility
1 Hz
4.5 km
10 Hz 800 km
100 Hz 150 km
0.00 Hz
...
10000.00
Hz Connect jumper X11 1-2
on CPU board for sound.
(Speaker not normally
installed on CPU board.
Audible sound repeats
the frequency signal.
Move your hand in the
sampling volume, and
you can check the
operation of FD12P.
Sound changes in range
130 ... 10000 Hz
depending on the object
movements in the sample
volume.
If no sound or no
change, check other
information of the
STA message.
VBB
absolute
VBB=Vb*2 - 1.2
V
when Vb=12 V
22.8 V
16 V /
25 V <16
>25
<21 V
>24 V
Power input for the
electronics is on the
CPU board, connector
X17, pin 4, pin 6: GND.
Vb voltage value
is +8.6 ... +13 V.