Service manual

RC2000 Service Manual Chapter 2 Theory of Operation 5
Research Concepts, Inc; 10679 Widmer; Lenexa, Kansas; USA 66215 WWW.RESEARCHCONCEPTS.COM
Chapter 2 THEORY OF OPERATION
2.1 System
Figure 2.1 (page 6) shows two views of the RC2000 chassis. Looking down on the controller from above
shows the transformer mounted in the left third of the housing, the drive board in the center, and the
digital board on the right. AC Power enter the housing through the back panel on the left. The LCD
display and keypad are mounted on the front near the drive and digital boards respectively.
Figure 2.2 (page 7) shows the interconnects between the major subassemblies of the RC2000. The
primaries of the transformer are connected to the power entry module through the front-panel switch /
circuit breaker. A secondary drive breaker is located in the back panel. AC power from the transformer
secondaries enters the drive and digital boards through Molex connectors. Ribbon cables provide the
interconnect between the digital board and the drive board, the keypad, and the display.
2.2 Digital Board
The digital board, shown in Figure 3 is 7 3/4 inches long, 5 3/4 inches wide, and 2 inches tall with the
installed components. The board contains two 16-pin header connectors J2 for the LCD display and J7
for the drive board. A single 14-pin header provides connection to the rotating feed drive option. The
back side of the board holds the 11-terminal interface connector, J1 and DB-9 female connector J5 that
in the communications interface.
The digital board for the RC2000 antenna controller, shown schematically in Figure 4, contains the 8097BH
micro-controller and its support peripherals, the interface to the 4 by 4 matrix keypad, the interface to the 2
row by 40 column LCD (liquid crystal display) module, the Programmable Logic Devices (PLD) which control
the solid state azimuth and elevation motor drives, the azimuth and elevation position sense pulse counters,
the analog voltage signal strength inputs (also referred to as the AGC inputs - Automatic Gain Control
inputs), the transceivers for the serial RS-422 serial port, the polarotor drive circuits, and the 5 volt power
supply.
2.2.1 8097BH Micro-Controller and Support Peripherals
The RC2000 is based on the Intel 8097BH micro-controller running at 10 MHz in the 8-bit bus mode. The
8097BH is a 16 bit micro-controller with 230 onboard 8 bit registers, an asynchronous serial port, an 8
channel 10 bit Analog to Digital converter, built-in timers, and a high speed I/O system.
The micro-controller and its support peripherals consists of the following components:
The 8097BH micro-controller (U1) is running at 10 MHz in the 8-bit interface mode.
An Intel 5C032 Programmable Logic Device (PLD) (U2) decodes the latched address and provides chip
select signals to the EPROM, static RAM (random access memory), real time clock (RTC), and parallel
port. The static RAM chip select line is active high; all other chip selects are active low.
The 74LS373 latch (U3) latches the lower 8 address bits. The upper address bits are latched by the micro-
controller. The controller software is stored in the 27C512 EPROM (electrically programmable read only
memory) (U4). The 27C512 is configured as 8 bits by 64 Kilobytes.