M520086-01
4-3
4.3 CALIBRATION AND ADJUSTMENTS
To perform the following calibration and adjustment procedures, the cover must be removed
from the power supply. Because removal of the cover allows access to potentially hazardous
power voltages (up to 253 VAC or 358 VDC) and because of the importance of accurate
readings to performance, only technically trained personnel should perform calibration
procedures.
WARNING
Hazardous voltages (up to 253 VAC or 358 VDC)
during equipment operations. Press power switch
to OFF position and disconnect power cable from
power source. Allow a minimum of 5 minutes for
discharge of storage capacitance before removing
the cover or performing any maintenance function.
Wear safety glass with cover removed.
The calibration Test Setup procedures require the following: remove prime power; connect the
power supply to a resistive load capable of full-rated voltage and current. Connect a precision
current shunt in series with either the positive or negative output between the power supply and
the resistive load. Two digital multimeters are required to perform the calibration procedures.
4.3.1
Converter Assembly Calibration
Voltage
Reference
The voltage reference is provided by an adjustable current regulator Q15. To calibrate
for the 1 mA programming coefficient (constant voltage), the following sequence is
recommended.
a.
Remove all jumpers and external connections to TB1-3.
b.
Set current control potentiometer on front panel fully counterclockwise.
c.
Connect a precision digital multimeter (DMM) to TB1-3(+) with reference to
TB1-7(-). Set DMM to DC milliamps and 2 milliamp range.
d.
Apply power to the power supply.
e.
Adjust R69 for 1.000 milliamps on DMM.
Current Reference
The current reference is a precision current source consisting of Q16 and associated
resistors. Calibration is accomplished by adjusting R71. The following sequence is
recommended.
a.
Remove all jumpers and external connections to TB1-8.
