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Appendix B. CNF4 Heater/Ventilator

B.4 Example B, CR3000 Datalogger Program with

Heater/Ventilator Control

The Program 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

simultaneously power the heater and ventilator.

Simultaneously powering the heater and ventilator will

exceed the current limit of the SW12 channel. If the heater

and ventilator need to be used at the same time, connect

the CNF4 to the 12V channel instead of the SW12 channel

and use an external relay to switch the power on and off.

Refer to Section 4.1 of the CR1000 and CR3000 manual

for details on the 12V current source limits.

CAUTION

'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

1 2 ... 45 46 47 48 49 50 51 52 53 54 55 ... 59 60

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Campbell CVF4 Specifiche Pagina 50

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