Fluke 726 [77/80] Calibrating thermocouple cjc

Calibrators

Calibration Adjustment

Calibrating Thermocouple CJC:

Connect the UUT as shown in Figure 35. For the lag bath setup, see Figure 36.

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Figure 35. Thermocouple CJC Calibration Connections

The calibration of the TC CJC (Cold Junction Compensation) is a critical part of the

calibration process, it is important that the thermocouple junction be allowed to

completely stabilize. Usually this takes a minimum of five minutes.

After the proper connections have been made, type “12” for 726/725 or “10” for 724, and

then press the Enter key on the PC keyboard. Use a lag bath to source a stable

temperature the 726. Enter the value of the temperature and the main calibration menu

will reappear. The temperature scale used is ITS-90.

Содержание

725 726 1
725 726 calibration manual 1
Calibration manual 1
Calibrators 1
Warranty 2
Table of contents 3
List of tables 5
725 726 6
List of figures 7
725 726 8
Contacting fluke 9
Introduction 9
Read first safety information 10
International symbols 11
725 726 12
Dc ma measurement and source 724 and 725 measurement only for 724 12
Dc voltage measurement 724 and 725 12
Dc voltage measurement and source 726 12
Dc voltage source 724 and 725 12
Note a count is the amount by which the least significant digit can vary 12
Performance and accuracy are specified for one year after calibration at operating temperatures of 18 c to 28 c 64 f to 82 f in relative humidity to 90 after a 5 minute warm up period 12
Specifications 12
Calibrators specifications 13
Dc ma measurement and source 726 13
Ohms measurement 724 and 725 13
Ohms measurement 726 13
Ohms source 724 and 725 13
725 726 14
Frequency measurement 725 14
Frequency measurement 726 14
Frequency source 725 14
Ohms source 726 14
Calibrators specifications 15
Frequency source 726 15
Millivolt measurement and source 724 and 725 15
Temperature thermocouples 724 and 725 15
725 726 16
Temperature thermocouples 726 16
Calibrators specifications 17
Temperature rtd ranges and accuracies 724 and 725 17
725 726 18
Rtd accuracy read and source its 90 726 18
Calibrators specifications 19
Loop power supply 19
Maximum current 22 ma 19
Pressure measurement 725 and 726 19
Pressure units availability 725 19
Pulse read and pulse source 726 19
Short circuit protected 19
Voltage 24 v 19
725 726 20
Cleaning the calibrator 20
Do not use aromatic hydrocarbons chlorinated solvents or methanol based fluids when cleaning the calibrator to avoid damaging the case never apply solvents to the calibrator 20
General specifications 20
If the calibrator requires cleaning wipe it down with a cloth that is lightly dampened with water or a mild detergent 20
Warning to avoid electric shock or damage to the calibrator never allow water inside the calibrator s case 20
Replacing the batteries 21
Remote control interface 725 and 726 23
725 726 24
Calibrators remote control interface 725 and 726 25
725 726 26
Calibration manual 26
Command response actions command arguments comment ch 1 ch 2 26
Serial command list 726 26
Table 5 lists the serial commands for the 726 and 725 calibrator with v3 0 and higher firmware refer to remote control interface 725 and 726 for activation steps 26
Table 5 serial command list 726 and 725 v3 0 and later 26
Upper_meas 26
Calibrators serial command list 726 27
Command response actions command arguments comment ch 1 ch 2 27
Freq_unit 27
Table 5 serial command list 726 and 725 v3 0 and later cont 27
725 726 28
Calibration manual 28
Command response actions command arguments comment ch 1 ch 2 28
Freq_level 28
Lower_meas 28
Pulse_freq 28
Table 5 serial command list 726 and 725 v3 0 and later cont 28
Trig 726 only 28
V_range 28
Calibrators serial command list 726 29
Cjc_state 29
Command response actions command arguments comment ch 1 ch 2 29
Cprt_max_t 726 only 29
Cprt_min_t 726 only 29
Cprt_r0 726 only 29
Rtd_type 29
Table 5 serial command list 726 and 725 v3 0 and later cont 29
Tc_type 29
Tsens_type 29
725 726 30
726 only 30
Calibration manual 30
Command response actions command arguments comment ch 1 ch 2 30
Cprt_coefa 726 only 30
Cprt_coefb 726 only 30
Cprt_coefc 726 only 30
Cprt_max_t 726 only 30
Cust1_alias 726 only 30
Cust2_alias 726 only 30
Cust3_alias1 30
Rtd_wire 30
Table 5 serial command list 726 and 725 v3 0 and later cont 30
Temp_unit 30
Cal_start 31
Calibrators serial command list 726 31
Command response actions command arguments comment ch 1 ch 2 31
Cust3_alias 726 only 31
Error codes 31
Hart_off 31
Hart_on 31
Table 5 serial command list 726 and 725 v3 0 and later cont 31
725 726 32
Equipment and software required to perform the procedures in this manual are identified in table 6 if the recommended equipment model is not available other equipment can be substituted if it meets the specifications indicated 32
Required equipment 32
Warning to avoid safety hazards and equipment damage during the calibration procedures use the specified calibration equipment listed in table 6 using unspecified equipment can give unreliable results and pose safety hazards 32
Performance tests 33
Preparing for the performance tests 33
Upper display voltage measurement tests 34
Lower display mv tc measurement tests 35
Lower display voltage measurement tests 36
Upper display ma measurement tests 37
Lower display ma measurement tests 725 and 726 38
Lower display frequency measurement test 725 and 726 39
Lower display frequency source test 725 and 726 40
Calibrators performance tests 41
Lower display 4 wire resistance measurement tests 41
Press on the uut on 726 until ω appears on the lower display if necessary use to get to the measure mode and use to get to the 4w mode measure should also appear on the lower display 41
Press stby on the 5520a 41
Set the 5520a to 2 wire output with 2 wire compensation off then make the connections shown in figure 8 41
Set the 5520a to source the resistance values in table 12 and verify that the uut resistance readings are within the limits shown 41
Lower display 3 wire rtd measurement 42
Lower display thermocouple measurement tests 43
Lower display thermocouple source test 44
Lower display ma source tests 725 and 726 45
Lower display mv source tests 46
Lower display voltage source tests 46
Calibrators performance tests 47
Lower display ohms source tests 47
Make the connections shown in figure 12 47
Press on the 726 on the uut until ω appears on the lower display if necessary press until source appears on the lower display 47
Set the fluke 8508a to 2 k range with loi off for 72x resistance 400 ω to 20 k ω with loi off range for 400 ω or more 47
Set the fluke 8508a to measure 4 wire resistance 47
The performance tests for the 724 are now complete disconnect and secure all test equipment 47
Use the arrow keys on the uut to set the uut output to the resistance values in table 18 and verify that the fluke 8508a readings are within the limits shown 47
Calibration adjustment 48
Pressure module input 725 726 48
725 726 50
Calibration manual 50
Calibration menu 50
Initiating communication 724 and 725 with v2 xx and lower firmware 50
Starting with the uut off push and hold while turning the uut on continue to hold until cal mode is displayed enter password appears on the display of all calibrators that have firmware version v1 1 or higher a password has been added to prevent users from accidentally changing the calibration of the calibrator the password for all 724 calibrators is 427 the password for all 725 calibrators is 527 50
The calibration menus as seen on the pc screen are as follows 50
Cal volts input 51
Calibration adjustment procedures 724 and 725 with v2 xx and lower firmware 51
Cal volts output 52
Cal ma input fluke 725 only 53
Cal ma output 725 only 54
Cal mv input 55
Cal mv output 56
Cal thermocouples 57
Cal ohms hi source 58
Cal ohms low source 59
Cal rtd low range 60
Cal rtd hi range 61
Cal iso volts 62
Cal iso ma 63
Calibration adjustment procedures 726 and 724 725 with v3 0 and higher 64
Initiating communication 64
Calibration menu 65
Calibration menu 725 calibration menu 65
Calibrators calibration adjustment 65
Calibrating isolated ma input 66
Calibrating isolated voltage input 67
Calibrating ma input fluke 725 and 726 only 68
Calibrating ma output fluke 725 and 726 only 69
Calibrating voltage input 70
Calibrating voltage output 71
Calibrating low ohms source 72
Calibrating high ohms source 73
Calibrating ohms measure 74
Calibrating thermocouple mv output 75
Calibrating thermocouple mv input 76
Calibrating thermocouple cjc 77
725 726 78
Replaceable parts 78
When servicing this calibrator use only the replacement parts specified user replaceable parts are listed in table 19 and shown in figure 36 78
Calibrators replaceable parts 79

Fluke 726 [77/80] Calibrating thermocouple cjc

Содержание

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