DynAmp RCEM, Инструкция по установке, эксплуатации и обслуживанию

Страница: 26 / 78

Installation, Operation and Service Manual RCEM
© 2012 DynAmp, LLC Page 12
43756 G
initialization sequence upon power-up. A “RCEM RESET” command from the
spreadsheet program will also cause the integrator resets to synchronize to the ac
line.
To work properly, each integrator must be reset when the associated rectifier device
is not conducting current during the commutation cycle. In a full-wave, three leg
rectifier, the reset pulse will occur at a different instant for each integrator on the
integrator card. The six integrator channels on each integrator card are referred to
as Leg 1, Leg 2, Leg 3, Leg 4, Leg 5, and Leg 6.
The integrator circuit outputs are scaled to 1V/1kA. The output of each integrator
circuit is available at the 12-position waveform output connector located on the top
edge of each integrator card. The integrator circuit outputs are also connected to
the pc board edge connector. These outputs are used by the reset sync cards to
generate the reset pulses. The final connection is to the RMS-to-dc converters.
This is the output signal path.
3.) RMS-TO-DC Converter.
The RMS-to-dc converters are used to convert the device current waveform to a dc
voltage. The outputs of the RMS-to-dc converters are connected to the 6-to-1
multiplexer.
4.) 6-to-1 Analog Multiplexer Circuit.
The multiplexer used is an eight input, one output CMOS analog multiplexer. Inputs
S1 through S6 are connected to the six RMS-to-dc converter outputs. Inputs S7
and S8 are not used. The output of the 6-to-1 multiplexer is connected to a non-
inverting amplifier with a gain of 5. This output is routed to the Personal Daq/56 via
the backplane and a wiring harness.
5.8 RESET SYNC CARDS
This circuit generates the reset pulses required to control the analog integrator circuits.
The device waveform signal from the integrator card is applied to a window comparator.
The outputs of the window comparators are connected to a microcontroller. The
microcontroller uses the ac zero-crossing signal from the backplane and the outputs from
the window comparators to generate the reset signals.
The first Reset Sync Card generates the reset signals for the first ten Integrator Cards
while the second Reset Sync Card generates the resets for the second group of ten
Integrator Cards. The reset signals are available on connectors P23 and P24 located on
the backplane. See Figure 5.2 for the Reset Pulse Connector Location and Figure 5.3 for
Reset Pulse Signal Location.