TB 9-6625-115-24
7. Equipment Setup
WARNING
HIGH VOLTAGE is used or exposed during the performance of
this calibration.
DEATH ON CONTACT may result if
personnel fail to observe safety precautions.
REDUCE
OUTPUT(S) to minimum after each step within the
performance checks where applicable.
a. To eliminate the potential for leakage current, clean TI binding posts and
surrounding area using alcohol and a lint-free cloth before beginning calibration.
b. Exercise each decade dial throughout its entire range three times in each direction.
c. Zero multimeter on 2 MΩ range and 20 V dc, 2V dc, and 200 mV dc ranges.
d. Set resistance standard to 10-0-0,-0-0-0-.0-1-0 Ω (1 MΩ). Using multimeter in a
1 ohm resolution for use in paragraph 8a. Resistance standard will remain on this setting
throughout the entire procedure.
NOTE
High-resistance measurements can be erratic and unstable.
These measurements are very sensitive to environmental noise
such as power line or RF pick up and changes in electrostatic
fields caused by people moving nearby. If erratic or unstable
measurements are observed, move away from the
measurement and stop all disturbances such as personnel
movements, drafts, opening and closing of doors, etc.
Activating the multimeter filter is also helpful.
8. Resistance Accuracy
a. Performance Check
(1) Connect equipment as shown in figure 1.
(2) Set TI to first switch position in table 3.
(3) Set multimeter to measure DCV, AUTO range. From CONFIG menu, activate
FILT.
(4) Set calibrator to 10 V dc, output to OPR.
(5) Record calibrator displayed output voltage as V.
(6) Allow multimeter time to stabilize then record indication as Vs.
(7) Calculate TI resistance (Rx) using formula below.
Rx = Rs [(V/Vs)-1]
Where:
V = calibrator output (10, 100 or 1000 depending on TI decade being calibrated).
Vs = multimeter indication in DC volts (i.e. 111.0987 mV = 0.1110987)