HP 98640A Installation And Reference Manual page 8

98640A
Analog Input Interface
Registers ................................................................. 3-3
])ata Registers .•.•...•....................•..•.......••...••••••.••.•••• 3-3
Pace Timi ng Regi ster •••..•••.....•..••.•.•.•.••...••.....•••.•..•••••••• 3-4
ID Regi ster ....•.•..................•................................... 3-4
Status Regi ster ..••...•......................•..............•...•....... 3-4
Analog Circui try ••.....•..............•.................•...•.........••.. 3-5
Vol tage Input ..•.•...•.•....•..........••.................•.•.•...•.•••. 3-5
Channe 1 Se 1 ec t ion .•......•...••..•
L' • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
3-6
Prograrrrnable Gai n Ampl i f ier (PGA) ..••..•••••••.....•......•..•••••...... 3-7
Gain of 1 ............................................................. 3-7
Other Gains .••.•...•...•....•....••...•.•.••.....•.•...••..•.••••...•. 3-9
Examp 1 e ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 3-9
Di fferent ial-to-Si ngle-Ended Converter ...•..•.....•....•.••..•.•..•.••. 3-1 0
Example •••••••••••••••••••••.•.••••••••••••••.••••••••••••••••••••• 3-10
Sample and Hold (StH) Circuit •.......•.••••..••••....•••.••.••.•.•..••. 3-10
Absolute Value Circuit .•••..••........••..••.•.......••..•..••••..•..•• 3-11
Analog-to-Digi tal Converter (ADC) ......•....•.•.•....••..•.••..•.•...•. 3-12
Corrmon Mode Over range Detect ion ........•......•.......••.••.••....•.... 3-13
Digital Conversion Circuitry ...••..••...••.••....•......•..•••••.•....•.. 3-13
Generating Control Signals .........•.•.•.•••.•....••.••.•••.•••.•.....• 3-13
Stopping the Counter .••.••••.....•....••..••••••...•.•••..•.•••.•...... 3-14
Conversion Cycle Timing .....•....••.•..•....••.....•.••...•.••...••.... 3-17
The BUSY
eye
Ie ......................................................... 3-18
The Internal Pacing Timer •...••....•••.••••••••••.••..•.•••.•.•...•..•• 3-19
External Pacing ..•...............•........•........•..•................ 3-20
Digi tal Backplane Circui try ..•.•...••....••••.••••.....•.•....••...•..••. 3-20
Select Code ••.••••.........•••...•...••••••....•...••.••.....•....••.•. 3-20
The Backplane Handshake ••..•••...•••...•.....•••••..........•••...•..•. 3-21
Addressing .•...•.•.•..•..•..•.•...•.••...••..•.....•..•..••.•••...•.•.. 3-21
Reset!! .........•..•..•.................•.....•......................... 3-22
Backplane Data Bus ...••..•.•....••........•.••....•••••...•.••....•..... 3-22
Reading From the Card ..•...•........•..•..••••....••.........•...•..... 3-22
Wri ting to the Card .•••..•.......••.••••..•..•.•...•.••...•.•••...•..•. 3-22
Interrupt5 .•.....•........................•............................ 3-23
Sequence of Operations .....•...•....•••.....•..............••.•.•..••.••. 3-23
The Analog Pipeline •...•.....•••.•...••..•.••..•.•.........•..••.•..•.... 3-25
PROGRAMMING AND EXTERNAL PACING
Programning Considerations .•.....•.......•....••........•...•.••.•..•.•.•. 4-1
Channel and Gain ...•.•.....•.....•..•.....•..•••............•.....•.•... 4-1
Dealing wi th Data •••.•.•....•.••..•....•.....•............•....••.....•. 4-3
Calibration .•••••..•••.....••......•....•...••.........••....•..•..... 4-3
Detailed Calibration ...............•..............•..••....•........ 4-4
Qu i c k Ca lib rat ion. . • . . . • . . . . . . . . • . . • . . • . . . . . . . . . . . • • . . . • . . . • . . . . . . • . 4 - 5
Over range!! ..••.••......•...•••....••......•••.......•.•.•.••.•••..••.. 4-7
Horrra 1 mode •••••••••••••••••.•••••••••••••••.••••.•••••••••••••••••• 4-7
COlll'non mode •.•...•.....•..•........•..•....•..........•...••.•••..•. 4- 7
Simple sample •••.•.•.•.•.....•............••.•......•...••••••..•.•... 4-7
Pace Interval ..•..........................•....•...•........•....••..... 4-9
No
i
Sf!! • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
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