20
Use with a data logger
BF5 User Manual v 2.3
Use with a data logger
The BF5 may be connected to an external data logger with readings being
taken continuously. The BF5 updates its output values four times per
second.
A logger with differential sensor inputs (rather than single-ended) is
recommended.
Diffuse and Total radiation {
mol m
-2
s
-1
(PAR) , Wm
-2
(Energy) , or klux
(Illuminance) } and Sunshine status outputs are available for logging.
Use cable type
SP-BF/w05
to connect to a data logger.
This can be extended using cable type
EXT/8w-xx
(where x = 5, 10 or
25m) up to a maximum of 100 m.
Data is presented at the analogue and digital outputs of the logger cable
within 100 ms of power being applied via the Power + wire.
Where daytime temperatures fall below zero, or inaccuracies due to
condensation are undesirable, make provision to provide power to the
heater (via cable type
SP-BF/w05
).
The heater power supply must be isolated, not sharing any earth return
with the BF5 sensor outputs.
Effect of engineering units on sensitivity and
resolution
The choice of output units has an effect on output sensitivities, as shown
in the following table:
Output units
Sensitivity
Resolution
Full scale
output
Molar
mol.m
-2
.s
-1
1mV =
1
mol.m
-2
.s
-1
0.6
mol.m
-2
.s
-1
2500mV = 2500
mol.m
-2
.s
-1
Energy
W.m
-2
1mV =
0.5 W.m
-2
0.3 W.m
-2
2500mV = 1250
W.m
-2
Illuminance
klux
1mV =
0.100 klux
0.060 klux
2000mV = 200
klux
Sunshine Status Output
The sunshine state output is a digital output, i.e. it has only two states, ON
and OFF. It uses a contact closure output (no sun = open circuit, sun =
short circuit).