Argantix KDC 100-100, User Manual

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User Manual
90 KDC Series II DC Power Supplies
7.6.2 CURR NOM Adjustment
Since the KDC controller is used for all output current range models, the internal reference
signals are normalized for each model using calibration DAC's. This normalization is generally
done at the factory and does not have to be repeated unless a power module has been replaced
or added to an existing unit in the field.
This normalized current reference signal is available at TP24 and also at the Auxiliary I/O DB9
connector (J21) if the -IF option is installed. See Table 3-6 for pin-out. If the -IF option is not
installed, the top cover has to be removed to access TP24 on the back of the controller board
behind the front panel. The normalized output current at these test points is 5.00 volts for full
scale output current, regardless of the model.
The first step in the adjustment of the normalized output is to establish a known current output
condition.
The procedure for adjusting the normalized output for current is as follows:
1. Attach an external precision shunt. Monitor the shunt current with an external DVM.
2. Apply a load that will give an output current more than 50% of the maximum rated current.
3. Make sure that the Current Limit is programmed to the maximum value.
4. Attach a DC voltmeter to TP24. Use TP1 for the DC voltmeter common.
5. Program the output voltage to obtain 50 % of max load current into the load.
6. Adjust the Inom DAC for a voltage at TP24 indicated by the following formula:
Use the formula below to determine correct TP24 test point measured voltage:
V (TP24) =5 x (Actual Output Current) / (Maximum Current Rating of Power Source)
Note: The Actual Output Current will change while adjusting the CURR NOM
DAC. If there was any change made to this adjustment, the output current
limit and current measurement must be re-calibrated. Refer to paragraph
7.4.2 and 7.5.2 respectively.
7.6.3 Master Configuration Change Calibration
If the same KDC II DC Supply is used both stand-alone and as the master unit of a multi-box
auto parallel configuration, it may be necessary to adjust the current programming calibration
when changing configurations. This applies to the master unit only. KDC II units with a
–AUX
option are set for use as auxiliary auto parallel units only. However, if a KDC II with the
–AUX
configuration is changed to a Master configuration and used as the master for other
–AUX units,
it too may require current programming calibration.
If a unit is frequency applied in different configuration settings, it is strongly recommended to
record the full scale current calibration coefficient for each mode of operation and enter the
correct value each time a unit is reconfigured. This avoids having to recalibrate the unit.
For instructions on how to perform full-scale current calibration, refer to sections 7.2 and 7.4.2.
To directly enter a calibration coefficient, unlock the calibration screens first as described in
section 7.2. Then select the OUTPUT calibration screen and scroll down to the CURR FS entry.
Change the coefficient to the desired setting using the Voltage knob.