KEPCO ATE-DMG SERIES - Manual (Page 58)

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3.7.3.10 TRIGGER SUBSYSTEM
This subsystem controls the remote triggering of the power supply.
3.7.3.11 [SOURCE:]VOLTAGE AND [SOURCE:]CURRENT SUBSYSTEMS
These subsystems program the output voltage and current of the power supply.
3.7.3.12 CALIBRATE SUBSYSTEM
The ATE-DMG series of power supplies support software-assisted calibration. A full calibration
consist of a voltage calibration and a current calibration. Both voltage and current 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 secret password (which has
been assigned to your power supply) will be provided. During the calibration, new calibration
data is computed which is than stored in the non volatile memory.
The following equipment is required for calibration: Digital Voltmeter (DVM) with 6 digits Dc
accuracy. Shunt 0.01 to 0.1 Ohm, 0.04%, minimum 100A, power > 100W (200W recom-
mended).
Because the voltage measured will be used as reference for calibration, the DVM itself must be
calibrated accurately. During voltage calibration, the voltage, overvoltage and voltage readback
are calibrated and during current calibration the current, overcurrent and current readback are
calibrated. The normal 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 voltage calibration all loads
must be disconnected and the sense terminals connected to the corresponding output termi-
nals. The digital voltmeter will be connected to the output of the power supply. For current cali-
bration 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.
3.7.4 PROGRAM MESSAGE STRUCTURE
SCPI program messages (commands from controller to power supply) consist of one or more
message units ending in a message terminator (required by Kepco power modules). The message
terminator is not part of the syntax; it is defined by the way your programming language indi-
cates the end of a line (“newline” character). The message unit is a keyword consisting of a sin-
gle command or query word followed by a message terminator (e.g., CURR?<newline> or
TRIG<end-of-line>). The message unit may include a data parameter after the keyword sepa-
rated by a space; the parameter is usually numeric (e.g., CURR 5<newline>), but may also be a
string (e.g., OUTP ON<newline>). Figure 3-9 illustrates the message structure, showing how
message units are combined. The following subparagraphs explain each component of the
message structure.
NOTE: An alternative to using the message structure for multiple messages defined in the fol-
lowing paragraphs is to send each command as a separate line. In this case each com-
mand must use the full syntax shown in Appendix B.