User Guide

Theory Of Operation Teledyne API M100E Analyzer Operation Manual
250
11.6.1.3. DISPLAY
The main display of the analyzer is a vacuum florescent display with two lines of 40 text characters each.
Information is organized in the following manner (refer to Figure 11-21):
Mode Field: Displays the name of the a
nalyzer’s current operating mode.
Message Field: Displays a variety of informational messages such as warning messages, operation data and
response messages during interactive tasks.
Concentration Field: Displays the actual concentration of the sample gas currently being measured by the
analyzer
Keypad Definition Field: Displays the definitions for the row of keys just below the display. These definitions
are dynamic, context sensitive and software driven.
11.6.1.4. KEYBOARD/DISPLAY INTERFACE ELECTRONICS
FRONT PANEL
Keypad
Decoder
Key Press
Detect
KEYBOARD
Beeper
Sample LED
(Green)
Cal LED
(Yellow)
Fault LED
(Red)
Display Data
Decoder
Display Power
Watchdog
From 5 VDC
Power Supply
I
2
C to Relay Board
Parallel Data
2 x 40 CHAR. VACUUM
FLUORESCENT DISPLAY
Display
Controller
Display Write
Clock
Serial
Data
I
2
C to/from CPU
Keyboard Interrupt Status Bit
I
2
C Interface
2
nd
Lang.
Switch
Maint.
Switch
Optional
Maintenance
LED
Figure 11-22: Keyboard and Display Interface Block Diagram
The keyboard/display interface electronics of the M100E Analyzer watches the status of the eight front panel
keys, alerts the CPU when keys are depressed, translates data from parallel to serial and back and manages
communications between the keyboard, the CPU and the front panel display. Except for the Keyboard interrupt
status bit, all communication between the CPU and the keyboard/display is handled by way of the instrument’s
I
2
C bus. The CPU controls the clock signal and determines when the various devices on the bus are allowed to
talk or required to listen. Data packets are labeled with addresses that identify information for the intended
device.
04515F DCN6048