KEPCO ABC-DM SERIES - Manual (Page 59)

ABC 040104
4-1
SECTION 4 - CALIBRATION
4.1 GENERAL
This section contains the calibration instructions for the Power Supply. It is recommended that
the user be familiar with Local Mode operation (PAR.3.3) before calibrating the unit.
A full calibration consist of a voltage calibration and a current calibration. Both voltage and cur-
rent calibrations consist of a zero and a full scale calibration. There are two ways to perform the
calibration: locally using the front panel keys or remotely sending commands through the GPIB
bus. These two ways cannot be combined.
In order to enter the calibration mode the correct calibration access code (password) must be
entered. If the password has been forgotten, call the factory and a special password (which has
been assigned to your power supply) will be provided. During the calibration, new calibration
data is computed which is then stored in the nonvolatile memory.
4.2 EQUIPMENT REQUIRED
The following equipment is required to calibrate the ABC Power Supply.
• Digital Voltmeter (DVM) with 6 digits d-c accuracy.
• Shunt Resistor: During the calibration procedure the LCD displays the minimum require-
ments for the shunt resistor. However, to avoid problems due to drift caused by heat dis-
sipation at higher power levels, Kepco recommends the following:
– ABC 10-10DM: 0.1 Ohm, 0.04%, 15A, 50W minimum (100W recommended)
– ABC 15-7DM: 0.1 Ohm, 0.04%, 15A, 50W minimum (100W recommended)
– ABC 25-4DM: 0.25 Ohm, 0.04%, 15A, 50W minimum (100W recommended)
– ABC 36-3DM: 0.25 Ohm, 0.04%, 15A, 50W minimum (100W recommended)
– ABC 60-2DM: 1.0 Ohm, 0.04%, 15A, 50W minimum (100W recommended)
– ABC 125-1DM: 1.0 Ohm, 0.04%, 15A, 50W minimum (100W recommended)
NOTE: Because the voltage measured will be used as reference for calibration, the DVM used
must be accurately calibrated prior to calibrating the ABC power supply.
4.3 CALIBRATION PROCEDURES
During voltage calibration, the voltage, overvoltage and voltage readback are calibrated and
during current calibration the current, overcurrent and current readback are calibrated. The nor-
mal procedure is to calibrate voltage first and then current. However, you do not have to do a
complete calibration each time. If required, you may calibrate only the voltage or the current and
then proceed to saving the calibration results. For either voltage or current calibration, BOTH
zero AND full scale calibrations must be performed.
For voltage calibration all loads must be disconnected and the sense terminals connected to the
corresponding output terminals. The digital voltmeter will be connected to the output of the
power supply. For current calibration after disconnecting all loads an appropriate shunt resistor
will be connected across output terminals and the digital voltmeter will be connected across the
sense terminals of the shunt resistor.