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Campbell Scientific CR1000 Measurement and Control System User Manual

Page 306

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Section 8. Operation

306 

 

 

Resolution

(p. 306)

lists high resolution ranges available for various thermocouple

types and temperature ranges. The following four example calculations of
thermocouple input error demonstrate how the selected input voltage range
impacts the accuracy of measurements. Figure Input Error Calculation

(p. 307)

shows from where various values are drawn to complete the calculations. See
Measurement Accuracy

(p. 278)

for more information on measurement accuracy and

accuracy calculations.

When the thermocouple measurement junction is in electrical contact with the
object being measured (or has the possibility of making contact) a differential
measurement should be made to avoid ground looping.

Table 65. Voltage Range for Maximum Thermocouple Resolution

Reference temperature at 20°C

TC Type and
Temperature

Range (°C)

Temperature

Range (°C)

for ±2.5 mV

Input Range

Temperature

Range (°C)

for ±7.5 mV

Input Range

Temperature

Range (°C)
for ±25 mV

Input Range

Temperature

Range (°C)

for ±250 mV

Input Range

T: -270 to 400

-45 to 75

-270 to 180

-270 to 400

not used

E: -270 to 1000

-20 to 60

-120 to 130

-270 to 365

>365

K: -270 to 1372

-40 to 80

-270 to 200

-270 to 620

>620

J: -210 to 1200

-25 to 65

-145 to 155

-210 to 475

>475

B: -0 to 1820

0 to 710

0 to 1265

0 to 1820

not used

R: -50 to 1768

-50 to 320

-50 to 770

-50 to 1768

not used

S: -50 to 1768

-50 to 330

-50 to 820

-50 to 1768

not used

N: -270 to 1300

-80 to 105

-270 to 260

-270 to 725

>725