ICS ELECTRONICS 4807, Инструкция по эксплуатации

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4-1
4
4
Theory of Operation
4.1 INTRODUCTION
This section describes the theory of operation for the 4867/2307/4867/2367.
The Analog-Digital Interface part of each product is identical. The differences
are in the GPIB or Serial Interfaces and in the power supply areas.
4.2 BLOCK DIAGRAM DESCRIPTION
A block diagram of the 4867 is shown in Figure 4-1. The 4867 is a
microprocessor based device that accepts commands from the GPIB (IEEE
488) bus to control its operation and the Analog-Digital Interface. The 4867
is made up of ten major elements, most of which are interconnected to the
microprocessor by a common data, address and control signal bus.
Incoming GPIB bus data and commands are received by the GPIB controller
chip. Each received character interrupts the microprocessor to accept GPIB
command and data characters When the command terminator is sensed, the
command characters are parsed and used to charge the 4867’s operational
settings or invoke some action or response. The typical action for the Model
4867 is to transfer data from the GPIB interface to or from the Analog-
Digital Interface.
At power turn-on time, the 4867 tristates the digital I/O lines, turns the relay
drivers off and sets the D/A outputs to 0 volts. The 4867 then performs a self
test of its critical circuits. Any self test fault is indicated by blinking a pattern
in the front panel LEDs. If the saved configuration data is corrupted, the
4867 will overwrite it with the factory settings and blink all of the LEDs. At
the end of a successful selftest, the 4867 will read the external GPIB address