GW Instek SPS Series User Manual

Page 24

7-3. Internal adjustments

The unit was accurately adjusted at the factory before shipment. So, readjustment is suggested only when the
accuracy of circuit is affected by the repair, or when you have the reason to believe that the unit is out of accuracy.
The recommended calibration device is a multi-meter with an accuracy of ±0.1% dcv or better. (GOOD WILL
model GDM-8145 or equivalent).

If readjustment is required, proceed the following procedure. Locations of the adjustments are shown in Fig. 6-1
and Fig.7-2.
(1) Adjustment of the Rating Voltage

A. Connect an accurate (±0.1%) external multi-meter to measure the dc voltage at output terminals of the power

supply.

B. Set the COARSE and FINE VOLTAGE controls to maximum (fully clockwise).
C. Adjust trimmer VR301 for a reading on the multi-meter to be 18.50V for SPS-1820, 36.50V for SPS-3610,

and 60.50V for SPS-606, 24.5V for SPS-2415, 12.5V for SPS-1230.

D. Adjust trimmer pot VR2 to set the reading value of voltmeter as same as the one shown on the multi-meter..

(2) Adjustment of the rating Current

A. Set the CURRENT control to HI.
B. Set the COARSE and FINE CURRENT controls to minimum (fully counterclockwise).
C. Set the COARSE and FINE VOLTAGE controls to the center position.
D. Connect an external multi-meter to measure dc current of output terminal.
E. Adjust trimmer VR304 to have a reading of –0.00A indicated on the current meter.
F. Set the COARSE and FINE CURRENT controls to maximum (fully clockwise)
G. Adjust trimmer VR303 for a reading on the multi-meter to be 20.10A for SPS-1820, 10.10A for SPS-3610,

and 6.10A for SPS-606, 15.1A for SPS-2415, 30.1A for SPS-1230.

H. Adjust trimmer VR2 to set the reading value of Amp-meter as the same as the one shown on the multi-meter.
I. Set CURRENT control to LOW.
J. Adjust trimmer VR310 to set the reading value of Amp-meter as 0.5 times to the rating current.
K. Adjust trimmer VR401 to set the OVP value (see Fig. 7-3).