Campbell Scientific CNR4 Net Radiometer - Manual (Page 54)

Appendix B. CNF4 Heater/Ventilator
B.4 Example B, CR3000 Datalogger Program with
Heater/Ventilator Control
Example B measures the four radiation outputs, thermistor temperature, and
controls the ventilator and heater using SW12V-1 and SW12V-2 channels on
the CR3000, respectively. In this example program, the ventilator and heater
can be turned on or off by manually setting the flag(1) and flag(2) high or low,
respectively. The program can be modified to include the conditional
statements to control the heater and ventilator based upon the environmental
parameters, such as light level and dew point temperature.
Do not use the SW12 channel of a CR1000 or CR3000 to CAUTION
simultaneously power the heater and ventilator.
Simultaneously powering the heater and ventilator will
exceed the current limit of the SW12 channel. If the heate
and ventilator need to be used at the same time, connec
Ref tion 4.1 of the CR1000 and CR3000 manual
for details on the 12V current source limits.
r
t
the CNF4 to the 12V channel instead of the SW12 channel
and use an external relay to switch the power on and off.
er to Sec
'CR3000 Series Datalogger
'
'CNR4 program
'This program measures CNR4 four-component net radiometer
'This program also measures the thermistor inside the CNR4
'In addition this program controls heater and ventilator
' using separate SW12V-1 and SW12V-2 channels
'The heater and ventilator are turned on/off by setting flag(1), and flag(2) high and low, respectively.
'
'
'User must enter the sensitivity values for all four probes in the program and save/compile
'prior to downloading it to the datalogger.
'Search for the text string "unique" to find places to enter the sensitivity values.
'
'Wiring Instructions
'
'ANALOG CHANNELS
'1H CNR4 Pyranometer Upper signal (red)
'1L CNR4 Pyranometer Upper signal reference (blue)
'gnd jumper to 1L
'
'2H CNR4 Pyranometer Lower signal (white)
'2L CNR4 Pyranometer Lower signal reference (thin black)
'gnd jumper to 2L
'
'3H CNR4 Pyrgeometer Upper signal (grey)
'3L CNR4 Pyrgeometer Upper signal reference (yellow)
'gnd jumper to 3L
'
'4H CNR4 Pyrgeometer Lower signal (brown)
'4L CNR4 Pyrgeometer Lower signal reference (green)
'gnd jumper to 4L
' CNR4 shield (clear)
'
'
B-8