SECTION 2
SPECIFICATIONS
8
2.1.2 VOLTAGE CONTROL SPECIFICATIONS (continued)
The UPC allows the Power Source to use any output TRANSFORMER RATIO from 0.01 to 5.11. Voltage
resolution for TRANSFORMER COUPLED MODE is as follows:
XFMR RATIO
Vresolution
.01 - 1.00
0.1 VAC rms
1.01 - 5.11
0.5 VAC rms
The default ratio is set by the TRANSFORMER RATIO SWITCH on the UPC METERING PCB (
).
The default value may be overridden by entering a new value in the UPC STATUS screen and in the
program to be executed. The power source must have an output transformer configured with the same
ratio as presently set for this feature to work properly.
TRANSFORMER RATIOs greater than 1.0 are step-up types.
TRANSFORMER RATIOs less than 1.0 are step-down types.
Accuracy is
±
0.5% of full scale over the range of ambient conditions with CSC disabled.
Accuracy is
±
0.05% of the voltage referenced to the internal voltmeter with CSC enabled.
NOTE
: TRANSFORMER RATIO is implied as a ratio to one, e.g.; a ratio of 2.5 is a ratio of 2.5:1.
NOTE
: The above voltages are power source output voltages. The UPC actually produces an RMS
voltage equal to (Power source output Vrms / 25 / TRANSFORMER RATIO). The SCU provides this type
of low voltage output at the rear panel connector, to be fed into a power source.
2.1.2.1 CSC (CONTINUOUS SELF CALIBRATION)
SPECIFICATIONS
The UPC includes a user
selectable “Continuous Self Calibration” function. When active, this function
maintains an accurate output voltage amplitude at the metering sense point, comparing the metered
voltage at that point to the set value and correcting for any difference. Accurate calibration of the voltage
metering function is essential for CSC to operate accurately.
When INT SENSE is chosen, CSC attempts to precisely maintain accurate COMMAND (Program) voltage
at the input side of the Output Relay of the power source.
To compensate for load voltage drops due to distribution losses, CSC can be effectively used to maintain
COMMAND (Program) voltage very precisely at the load by selecting EXT sense with sense leads
connected at the load and having CSC enabled.
Basic properties of the CSC function are:
1.
Voltage level held to
±
0.05% of the program voltage referenced to the internal voltmeter with CSC
enabled.
2.
Response time varies anywhere from 1 mSec. to 300 mSec. and only responds while the UPC is
metering, not while in Program Edit or Setup mode.
3.
CSC operates independently of selected waveform, does not increase distortion and is stable into
any PF load.
4.
Automatically switches between internal and remote voltage sensing as the metering function is
switched between INT and EXT.
5.
CSC does NOT function during Transients or Transition Time functions.
6.
CSC will only correct the Output Voltage by ± 15%. If the sense voltage is not within ± 15% of the
COMMAND voltage, CSC will become disabled until the Output Voltage is within ± 15% of the
COMMAND voltage. Each phase operates independently.
