11
5
CONFIRMING THE OUTPUTS
If you wish to test the outputs of the sensor, u
se the command ‘TEST’ to get the unit to
temporarily output foggy and clear conditions, which will allow you to check the analogue
outputs and (optional) relay thresholds. Use the CO command before the TEST command to
access the TEST command.
The command structure is:
TEST,tt,vv.vv,f,c
Where:
tt = Duration of test in minutes
range 00-60 (00 will stop the test)
vv.vv = Visibility will be in km
range 0.01 to 75.00
f
= Fault Indicator
0=No Fault, 1 = Fault
c
= Contamination Indicator
0=None, 1=Warning, 2=Alert
Example:
TEST,
02,07.50
,0,0,00
–
Outputs a visibility of
7.5
km for
2
min (Clear conditions)
TEST,
06,00.10
,0,0,00
–
Outputs a visibility of
0.1
km for
6
min (Foggy conditions)
5.1
ANALOGUE SIGNAL CHECKS
Using a multimeter, set to measure voltage or current as appropriate, measure the
connections (J12 H & I (0-10V), or J & K (optional 4-20mA output)) and ensure the output
changes when the different conditions are simulated.
Note: The current output should not
be terminated with a resistance greater than 500 Ω to
enable a maximum of 20mA to be available. The voltage should be read across a resistor
greater than 10K Ω.
The RWS analogue outputs can be configured for MOR or EXCO (default) output (See
manual for details). Use the following formulas to convert voltage or current readings to
MOR or EXCO.
0-10v
4-20mA (Optional)
MOR output
MOR=(Range/10)* Vout
MOR=(Range/16)*(mAout - 4)
EXCO output
EXCO=(300/10)*Vout
EXCO=(300/16)*(mAout - 4 )
Range is the maximum configured range of the sensor (EXCO range fixed at 300)
Vout = The voltage across the 0-10V output terminals
mAout = The current flowing through the 4-20mA terminals in milliamps
5.2
RELAY CHECKS
Use a multimeter to monitor the relay outputs, whilst simulating high and low visibility.
Please note, to prevent repeated switching around the threshold value, the relays have a
timer delay and hysteresis built in, the relays can take up to 5 mins to change.
Please follow local health and safety procedures if hazardous voltages or currents are
present. If in doubt de-energise and disconnect the wires to the relays, and confirm the
relays operation through resistance measurement.
