Lamar Technologies BETA D-50 - Manual (Page 26)

5. CALIBRATION AND MAINTENANCE
J.
COMPARE READINGS
Compare the Beta D-50 digital ammeter with the external millivolt meter. The
external meter reads the millivolt drop across a 50 ampere/50 millivolt shunt.
Every millivolt read on the external millivolt meter represents 1 ampere. The
readings should be within ± 0.2 millivolts (amperes).
a. If readings differ less than ± 0.2 millivolts, the ammeter is accurately
calibrated. Turn AC power off and disconnect battery.
b. If readings differ more than ± 0.2 millivolts, continue with steps K through M.
K.
REMOVE THE COVER
If voltmeter differs more than ± 0.2 amperes (millivolts), remove the unit’s L-
shaped cover by unscrewing the four screws
a. Two on top left side of unit
b. Two on bottom right side of unit
WARNING: Calibration needs to be performed with the unit’s cover removed as
well as both mains power and battery connected. It should only be performed by
trained personnel. If performed incorrectly it could result in electrical shock
leading to injury or death.
L.
CALIBRATE AMMETER
The ammeter can be found on the back side of the front panel. Locate the
ammeter trim pot.
Using a 1/16 inch (2 mm) slot blade precision type screw driver, adjust the
embedded trim pot located at the rear of the ammeter. Adjust until ammeter
reading matches that of the calibrated millivolt meter (at least within ± 0.2
amperes or millivolts).
M.
REPEAT FOR ADDITIONAL CURRENT SETTINGS
To verify the accuracy over the range of the meter, additional current settings
could be checked. Since the Beta D-50 digital meters are linear, checking two or
three current settings are adequate to verify the range. The easiest way to
check additional current settings is to repeat steps I and J but setting a lower
discharge current in step I.
Page 24 BETA D-50 TESTER / ANALYZER - OPERATING MANUAL V2.2