Fluke 1502A 8 Calibration Procedure

8 Calibration Procedure

The 1502A uses a three-pointcalibration scheme with a quadratic polynomial

correction function to maintain the accuracyof its resistance measurement. The

three calibration points are at 0Ω, 100Ω, and 400Ω.Three calibration pa-

rameters determine the correction function:CAL0, CAL100, and

CAL400.The CAL0 parameter sets the correction at 0Ωresistance (but

does not affectthe correction at 100Ω).The CAL100 parameter sets the

correction at 100Ωresistance (but does not affectthe correction at 0Ω).

The CAL400 parameter sets the correction at 400Ωresistance (but does

not affectthe correction at 0 and 100Ω). Adjusting the calibration param-

eters directly affects themeasurem entat the specific resistances.For

example,increasing the CAL100 parameter by 0.005 increases the

measured value at 100Ωby0.005Ω.

The calibration parameters are accessed inthe Cal menu. Th e calibration pa-

rameters are protected by requiring thecorrect password to access them. Press

the Menu button,“SEt?” appears. Press the Ω/Exit button and hold it down

for one second, “CAL” appears briefly.The display will show “PA= 0000”and

allowyou to change the number to the correct password. You must enter the

password(“2051”). Usethe Land Rbuttons to move between the password

digitsand the Uand Dbuttons to increase or decrease the value of a digit.

Press Enter when all the digits are correct. If the password is entered correctly

the firstparameter in the calibratio n menu will appear.

The firstparameter inthe Cal menu is the lockout control parameter, indicated

on the display as “LOCOUt”. This parameter has two options, “CAL”and

“ALL”. “CAL” (default) locks out the calibration menu only. “ALL” locks out

all menusand access to any menu requires the correct password. Use the L

and Rbuttonsto select the lockout option and press Enter to continue. The

instrument calibration parameters follow.

The calibration parameters appear with thename shown briefly then the value.

Youcan change the sign and digits of each parameter. Use the Land Rbut-

tons tomove between digits and the Uand Dbuttons to increase or decrease

the valueo f the digit. Press Enter to saveth e newvalue.

The last parameter in the Cal menu is the factoryr esetfunction. This can be

used to clear the internalmemory and reset all parameters to the defalut values.

This isintended to be used only at the factory.

The calibrationparameters can also be set using remote commands through the

RS-232 or IEEE-488 interface.The *PA=<password><EOS> command must

be used first,using the correct password (“2051”), to enable access to the cali-

bration parameters. Lockoutprotection is automatically set by cycling the

8 Calibration Procedure

Accessing the Calibration Parameters