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GE Grid Solutions
D20/D200 Technical Overview
GE Information
PRPI-019-3.00-10
49
The analog input section consists of a filter and solid-state multiplexer, a variable-gain amplifier,
an integrating voltage-to-frequency converter, a programmable timer, a CPU time register and
miscellaneous support circuitry. Figure 31 is a block diagram of the analog input peripheral.
Precision
Scaling
Resistors
SWC and
Impulse
Protection
Filter and
Analog Mux
D20A Termination Board
D20A Logic Section
Input
1 - 8
9 - 16
17 - 24
25 - 32
Voltage
References
0, +/-1, +/-5, +/-10
Temperature
Transducer
Reference
PGA
PTM
MCU
Voltage to
Frequency
Converter
PPI
Opto
Gain
Select
Opto
Input
Select
OPTO
PPR
OPTO
SYNC
Switch Mode
Power Supply
+12V
PGA
Ranges
0.5
1
5
Analog Input Ranges
50 mA
20 mA
10 mA
5 mA
1 mA
10 V
5 V
1 V
Legend
MCU.......... Microcontroller Unit
OPTO........ Optical Isolator
PTM...........Programmable Timer Module
PPI............ Parallel Peripheral Interface
PPR...........Pulse Position Resolver
Clock
50/60 Hz
Figure 31 D20A Analog Input Peripheral Block Diagram
2.4.7.1 Analog Conversion Process
Figure 32 provides an overview of the analog conversion process.
INPUT
ADAPTER
AMPLIFIER
DIVIDER
VOLTAGE TO
FREQUENCY
AUTO-ZERO
Figure 32 Analog Conversion Process