Campbell Scientific CR23X Micrologger - Manual (Page 144)

SECTION 9. INPUT/OUTPUT INSTRUCTIONS
9-10
TABLE 9-5. Voltage and Temperature Ranges for Thermocouples
if the Reference is 20
°°°°
C
Voltage
Range
Type T Type E Type K Type J
±
10 mV -200 to 227 -199 to 169 -56 to 264 -150 to 205
±
50 mV -200 to 400 -240 to 675 -56 to 1372 -150 to 422
±
200 mV ----- -240 to 1000 ----- -----
Voltage
Range
Type B Type R Type S Type N
±
10 mV 50 to 1260 0 to 970 -50 to 1045 -200 to 333
±
50 mV 50 to 1700 0 to 1450 -50 to 1450 -200 to 1240
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Repetitions
02: 2 Range code (Table 9-1)
03: 2 Single-ended channel
number for first TC
(when indexed (--),
becomes an input
location containing
voltage measurement)
04: 2 Thermocouple type
code (Table 9-4)
05: 4 Reference temperature
location
06: 4 Destination input
location
07: FP Multiplier
08: FP Offset
Input locations altered: 1 per repetition
*** 14 THERMOCOUPLE TEMPERATURE, ***
DIFFERENTIAL MEASUREMENT
FUNCTION
This instruction calculates the thermocouple
temperature for the thermocouple type selected.
The instruction specifies a DIFFERENTIAL
VOLTAGE MEASUREMENT (Section 13.2) on
the thermocouple, adds the measured voltage
to the voltage calculated for the reference
temperature relative to 0°C, and converts the
combined voltage to temperature in °C. A
multiplier of 1 and an offset of zero yields
temperature in degrees Celsius.
When using the
±
10,
±
50, or
±
200 mV ranges,
the differential inputs are briefly tested to insure
that the thermocouple is not open. If the
thermocouple is open, -99999 or -6999 is
output.
NOTE: Because of the open thermocouple
test, high output impedance sensors should
not be measured with P13 or P14.
Table 9-4 gives the thermocouple type codes
for Parameter 4. Enter a 9 in front of the code
and the CR23X will make a check on common
mode range; -99999 is output for temperature if
common mode range is exceeded.
To skip the measurement portion of Instruction
14 and apply the CSI polynomials to a millivolt
value in an input location, index parameter three,
input channel. The input location where the
thermocouple output (mV) is located is now
defined by parameter three. The thermocouple
must be measured with Instruction 2.
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Repetitions
02: 2 Range code (Table 9-5, 9-1)
03: 2 Differential channel
number for first TC
(when indexed (--),
becomes an input
location containing
voltage measurement)
04: 2 Thermocouple type
code (Table 9-4)
05: 4 Reference temperature
location
06: 4 Destination input
location
07: FP Multiplier
08: FP Offset
Input locations altered: 1 per repetition