Basler Electric DECS-100 - Manual (Page 27)

9287500991 Rev M DECS-100 Functional Description 3-3
If the Var/Power Factor Control option is present and is enabled in the software, the 52J/K input has
priority. Therefore, if the 52J/K and the 52L/M inputs are both open, the system operates in var/power
factor mode. For more information, see Voltage Matching Control Option.
Voltage Matching Control Option
If the Voltage Matching option is enabled in the software, closing a contact across terminals VM and VMC
causes the DECS-100 to operate in the voltage matching mode. An open contact disables voltage
matching. Voltage matching is also disabled when either the 52J/K or 52L/M inputs are open.
RS-232 Communication Port
The communication port provides the interface for user programming (setup) of the DECS-100.
Connection is made to the female RS-232 (DB-9) connector with a user-supplied, standard 9-pin cable.
The communication port is optically isolated and is powered from a transformer-isolated supply.
Microprocessor
The microprocessor is the heart of the DECS-100 and performs measurement, computation, control, and
communication functions by the use of its embedded programming and the nonvolatile settings stored in
its memory.
Power Input Stage
Input power applied to terminals 3, 4, and 5 is rectified and filtered before being applied to the power
amplifier and the power supply. Input power may be single-phase or three-phase in the range of 88 to 250
Vac at a frequency of 50 to 400 hertz.
The input power source should be properly fused for the application.
Power Supply
The internal switch-mode power supply receives power from the power input stage and supplies power at
the required dc voltage levels to the internal circuitry of the DECS-100.
Power Amplifier Stage
The power amplifier receives power from the power input stage and supplies a controlled amount of
power to the exciter field via terminals F+ and F–. The amount of power supplied to the exciter field is
based on gating pulses received from the microprocessor. The power amplifier uses a solid state power
switch to provide the required power to the exciter field. Power amplifier output to the field is rated up to
63 Vdc at 7 Adc continuous and 135 Vdc at 15 Adc for 10 seconds.
Front Panel Indicators
Eight front-panel LED indicators light to indicate various protective functions and operating modes.
Section 2, Human-Machine Interface provides more information about the front panel indicators.
Relay Output
A common alarm output contact is provided through terminals AL1 and AL2. This normally open, form A
contact annunciates alarm or trip conditions. The relay output is latching.
DECS-100 OPERATING FEATURES
The following paragraphs describe the characteristics of each DECS-100 operating feature.
Operating Modes
The DECS-100 provides up to four modes of operation selectable through BESTCOMS™ software.
Automatic voltage regulation mode and Manual mode are standard features. Var and Power Factor
modes are an option.
Automatic Voltage Regulation Mode
In Automatic Voltage Regulation (AVR) mode, the DECS-100 regulates rms generator output voltage.
This is accomplished by sensing generator output voltage and adjusting dc output excitation current to
maintain voltage at the regulation setpoint. The regulation setpoint is adjusted by the Raise and Lower