Communications - Teledyne 6400A Instruction Manual

Sulfur dioxide analyzer
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TAI Model 6400A SO
Analyzer Operator Manual, 02164, Rev. G
2
9.3.1.3 Front Panel Keyboard
The keyboard consists of 8 keys and 3 LED's. Key strokes are sent to the SBC40 computer's
parallel port. The computer software detects the key strokes via interrupts. The bottom line of the
display consists of 40 characters which is divided into 8 - 5 character fields. Each field defines
the function of the key immediately below it. The definition of the keys is variable and depends
on the menu level of the software.
To check the operation of the keyboard, each key should perform an operation indicated by its
current definition shown on the second line of the display.
Example 1 - testing key #1 (left most key).
At the top level menu key #1 is defined as the TEST function. Pressing this key should cause the
middle field of the top line of the display to show the various test functions.
Example 2 - testing key #8 (right most key). At the top level menu key #8 is defined as the
SETUP key. Pressing key #8 should cause the SETUP menu to be displayed.
Example 3 - If the 5 character field above any key is blank, the key is not defined, pressing the
key has no effect.
The 3 status LED's indicate several functional states of the instrument such as calibration, fault,
and sample modes. The state of the LED's is controlled by 3 lines on the parallel port of the
SBC40. Functioning of the LED's can be checked by:
Turn off the 6400A power.
1. While watching the LED's, turn on the instrument power.
2. When the power comes up, the computer momentarily applies power to all 3 LED's for
approximately 1 sec. If all the LED's are observed to light, they are working properly.
9.3.2 RS-232 Communications
The 6400A uses the RS-232 communications protocol to allow the instrument to be connected to
a variety of computer based equipment. RS-232 has been used for many years and is well
documented. Generally, every manufacturer observes the signal and timing requirements of the
protocol very carefully. Problems arise when trying to specify connectors, and wiring diagrams
that attach the analyzer to various devices.
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