Keithley 2750 User Manual

F-2 Temperature Equations Model 2750 Multimeter/Switch System User’s Manual
Thermocouple equation
The Model 2750 uses the ITS-90 inverse function coefficients for the polynomial to calcu-
late thermocouple temperature. The Model 2750 measures the thermocouple voltage, and
then calculates temperature (in °C) as follows:
t
90
= c
0
+ c
1
E + c
2
E
2
+ c
3
E
3
... c
i
E
i
where: t
90
is the calculated temperature in °C.
c
0
, c
1
, c
2
, c
3
... c
i
are the coefficients for the thermocouple type.
E is the thermocouple voltage in microvolts (µV).
The coefficients for each thermocouple type are listed in Table F-1 through Table F-8.
Table F-1
Type B inverse function polynomial
250ºC to 700ºC
(291µV to 2,431µV)
700ºC to 1,820ºC
(2,431µV to 13,820µV)
c
0
=
c
1
=
c
2
=
c
3
=
c
4
=
c
5
=
c
6
=
c
7
=
c
8
=
Error:
9.842 332 1 × 10
1
6.997 150 0 × 10
-1
-8.476 530 4 × 10
-4
1.005 264 4 × 10
-6
-8.334 595 2 × 10
-10
4.550 854 2 × 10
-13
-1.552 303 7 × 10
-16
2.988 675 0 × 10
-20
-2.474 286 0 × 10
-24
0.03°C to -0.02°C
2.131 507 1 1 × 10
2
2.851 050 4 1 × 10
-1
-5.274 288 7 1 × 10
-5
9.916 080 4 1 × 10
-9
-1.296 530 3 1 × 10
-12
1.119 587 0 1 × 10
-16
-6.062 519 9 1 × 10
-21
1.866 169 6 1 × 10
-25
-2.487 858 5 1 × 10
-30
0.02°C to -0.01°C
t
90
= c
0
+ c
1
E + c
2
E
2
+ c
3
E
3
... c
i
E
i
where: t
90
is the calculated temperature in °C.
E is the measured voltage in microvolts.
2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM

Keithley 2750 Specifications

General

Interface	GPIB, RS-232, Ethernet
Switching Speed	Up to 500 channels/second
Maximum Voltage	300V
Operating Temperature	0°C to 50°C
Measurement Functions	DCV, ACV, DCI, ACI, 2-wire Resistance, 4-wire Resistance, Frequency, Temperature
Resolution	6.5 digits
Current	1A
Maximum Current	1A