Assembly Instructions

MXI1503-2004 CONTROL UNIT
PUB13-09 Rev 1 27
4 MAIN CONTROL BOARD
This section describes the 31C1972 CPU Board (referred to hereafter as the Main CPU Board).
This Printed Circuit Board (PC Board) is the communications center of the transmitter where all serial communications
throughout the transmitter system are routed. This PC Board also handles the basic remote control functions of the
transmitter system.
The CPU Board is located in the rear of the control chassis with the interface connectors protruding through the rear
panel.
Figure 15 CPU Board Shown Mounted in the Control Chassis
The CPU Board communicates serially each amplifier and the Front Panel Interface board. The Information that is
sent to the Front Panel Interface board gets pass through to the Touch Screen. The board also has a 9-Pin D RS232
connector and an Ethernet RJ-45 connector that are allocated as remote ports.
The CPU Board incorporates five remote inputs, three telemetry outputs and six status outputs. These are used for
remote interface to a customer-specific remote control system. The remote signals generated by the CPU Board
comprise the basic remote functions that would be required.
The following sections detail the function and implementation of the circuitry on the CPU Board.
4.1 GENERAL LAYOUT AND SUBSYSTEMS
The CPU Board can be divided into a number of logical sections that make it easier for the operator to understand
which functions the board is performing. These systems are the Serial Communication, RF Metering, On/OFF Relay
Control, Remote Controls and Status, Information Storage, and Rear Panel Interface.
4.1.1 Serial Communications
The CPU Board has three asynchronous RS232 serial ports called SCIs however the CPU board requires seven serial
communication lines to communication with up to four Amplifiers, the Touch Screen, the Remote RS232 port and the
Ethernet Port. To get the required number of serial ports the micros extended addressing lines are used to
communicate with two UARTs. This provides a total of 8 serial ports that can be accessed and read by the micro
processor.