Operator`s manual

SECTION 9. INPUT/OUTPUT INSTRUCTIONS
9-6
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Repetitions
02: 2 Input channel number of
first measurement
03: 2 Excitation channel
number
04: 4 Input location for first
measurement
05: FP Multiplier
06: FP Offset
Input locations altered: 1 for each thermistor
channel
*** 12 207 RELATIVE HUMIDITY PROBE ***
FUNCTION
This instruction applies a 3 VAC excitation
across Campbell Scientific's Model 207
Temperature and RH Probe, makes a fast
single-ended measurement across a series
resistor on the 150mV range, calculates the
result with a fifth order polynomial, and performs
the required temperature compensation before
outputting the result in % RH.
When measuring several probes, all the RH
elements should be connected sequentially.
The temperature values used to correct the RH
measurements should also be stored
sequentially to make use of the REP feature in
Instruction 11.
NOTE: The temperature value used
in compensating the RH value
(Parameter 5) must be obtained (see
Instruction 11) prior to executing
Instruction 12.
The RH results are placed sequentially into the
input locations beginning with the first RH value.
In the 207 probe, the RH and temperature
elements use a common excitation line. NEVER
EXCITE THE 207 PROBE WITH DC
EXCITATION (this includes ohm meters) as the
RH chip will be damaged.
The maximum error from the polynomial used
for calculating RH is given here:
Range (%RH) Error (%RH)
10 - 100 ±4
15 - 94 ±1
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Repetitions
02: 2 First channel for RH
measurement
03: 2 Excitation channel
number
04: 4 Input location for first
compensating
temperature
measurement
05: 4 Input location for first RH
measurement
06: FP Multiplier
07: FP Offset
Input locations altered: 1 for each RH
measurement
*** 13 THERMOCOUPLE TEMPERATURE, ***
SINGLE-ENDED
FUNCTION
This instruction uses the selected thermocouple
calibration to calculate the thermocouple output
voltage at the reference temperature, then it
makes a SINGLE-ENDED VOLTAGE
MEASUREMENT (Section 13.2) on the
thermocouple and adds the measured voltage
to the calculated reference voltage, then
converts the voltage to temperature in
o
C.
Select the smallest voltage range that will
accommodate the temperatures being
measured (Table 9-4).
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Repetitions
02: 2 Range code
03: 2 First TC channel
04: 2 Thermocouple type code
05: 4 Reference temperature
location
06: 4 Destination input location
07: FP Multiplier
08: FP Offset
Input locations altered: 1 for each
thermocouple channel