Appendix C. CNF4 Heater/Ventilator
C-8
TABLE C-1. Data Logger Connections for Differential Measurement
with Heater/Ventilator Control
Function
Wire
Colo
u
r
Data Logger Terminal
Thermistor
Thermistor Signal
White
U
configured for single-ended
analog
ue
input
1
,
SE
(single-ended,
analog
ue
-voltage input)
Thermistor Voltage
Excitation
Red
U
configured for voltage excitation
1
,
EX
,
VX (
voltage excitation)
Thermistor Signal
Reference
Black
⏚
Shield
Clear
⏚
CNF4
Heater/Ventilator
Ventilator Power
Yellow
SW12V
Ventilator Ground
Brown
G
Tachometer Output
Green
P
(pulse),
C
(control)
Tachometer Ground
Grey
G
or
⏚
Heater Power
White
SW12V
Heater Power
Black
SW12V
Heater Ground
Red
G
Heater Ground
Blue
G
Shield
Clear
⏚
1
U
terminals are automatically configured by the measurement instruction.
2
Jumper to
⏚
with a user-supplied wire.
Pull back wires for Pt-100 (grey, brown, green, and yellow), which are not in
use, and tie them around the TEMP cable using a cable tie or electrical tape to
avoid possible damage to the Pt-100, due to electrical short circuit.
Do not use the data logger switched 12 V to simultaneously
power the heater and ventilator. Simultaneously powering
the heater and ventilator will exceed the current limit of the
switched 12 V terminal. If the heater and ventilator need to
be used at the same time, connect the CNF4 to the 12V
terminal instead of the switched 12 V terminal and use an
external relay to switch the power on and off.
C.4 Data Logger Programming for Heater/Ventilator
Control
The data logger program can measure the four radiation outputs and thermistor
temperature, read the tachometer, and control the ventilator and heater based on
temperature and relative humidity measurements. The tachometer is measured
using a
PulseCount()
instruction configured for low-level AC. A sensor such
as the EE181 can provide the temperature and relative humidity measurements.
The SW12 terminal cannot provide enough amperage for the CNF4. Therefore,
CAUTION