KEPCO MST Series - Manual (Page 40)

3-8
MST SERIES 061813
3.8 CALIBRATION
Calibration of the MST Power Module is recommended for any of the following conditions.
• The unit has been moved.
• Operating environment (temperature, humidity, etc.,) has been altered.
• Periodic maintenance determined by user.
• Inaccurate measurements are suspected.
Perform the procedures outlined below in sequence (see Figure 2-4 for the location of calibra-
tion controls). Calibration adjustments are recommended only when the test point value
exceeds the indicated tolerance on the measured value. Note that the measured value toler-
ance is generally an order of magnitude looser than the adjustment tolerance. This avoids
unnecessary recalibration, while providing a precision adjustment if calibration is required.
NOTE: E
MAX
is the maximum output voltage of the unit listed in Table 1-1; I
MAX
is the maxi-
mum output current of the unit as listed in Table 1-1 for 45° C.
3.8.1 EQUIPMENT REQUIRED
Calibration of MST Series Power Modules requires the following equipment:
• Host computer
• RA 55 or CA 400 Rack Adapter, or Input Power/Communication Cable (see Table 1-3)
• Controller Module (Kepco MST 488-27 or TMA Series)
• Digital Voltmeter (DVM): 6½ digit display, 10 µV resolution
• Precision Current Shunt: R
SHUNT
< 0.02 (EMAX / IMAX) Ω
where: E
MAX
= rated Power Module output voltage (e.g., 36V for MST 36-5)
I
MAX
= rated Power Module output current (e.g., 5A for MST 36-5)
NOTE: To avoid errors due to temperature drift of the shunt, a power rating of
greater than 10 times actual dissipation is recommended. The above calcu-
lation results in a maximum shunt power dissipation of less than 4W, a 100W
shunt is adequate for all models)
• Miscellaneous programming interface cables, load cables, etc.
Install the MST Series power module under test (UUT) in the calibration test set-up shown in
Figure 3-1