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ND820 ANALOG TO DIGITAL CONVERTER¶

INTRODUCTION¶

The ND820 – Analog to Digital Converter – is a low cost medium performance data acquisition system intended for laboratory, instrumentation and process applications. The Converter requires one standard I/O slot.

PRODUCT DESCRIPTION¶

The Analog to Digital Converter is physically located on one standard size NORD-10/NORD-12 module. The Converter is self-contained with power such that it may be plugged directly into a standard I/O slot.

The Converter may be operated in three different programmable modes:

Sampling is program controlled.
Sampling may be started by the EXTERNAL signal. An interrupt is at End of Conversion sent to the CPU. Sampling accuracy is in this case determined by the EXTERNAL signal.
The EXTERNAL signal may be used to generate an interrupt to the CPU and the sampling is then program controlled.

FEATURES¶

12 bits resolution
8 bipolar inputs
input filter
overvoltage protection
external "Start Conversion" facility for high sampling accuracy

Diagram¶

graph TD;
    A[Channel] -->|0| M;
    A -->|1| M;
    A -->|2| M;
    A -->|3| M;
    A -->|4| M;
    A -->|5| M;
    A -->|6| M;
    A -->|7| M;
    M[Input Filter\nMUX] --> B[Analog/\nDigital\nConverter];
    B -->|Start\nConversion| C[Control\nLogic];
    C -->|12 bit Data| D[Standard NORD-10/NORD D-12 I/O Bus];
    M -->|MUX Address A0-2| D;
    M -->|EXTERNAL| D;
    D -->|Interrupt| C;
    subgraph E [ ];
        F[Regulated\nPower\nSupply]
    end

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SPECIFICATIONS¶

Hardware¶

Feature	Specification
Resolution	12 bits
Number of channels	8
Input voltage	± 10V differential
Converted data	2’s complement notation
Input filter	100 ms time constant
Conversion time for A/D	25 µs
Total data acquisition time	35 µs
Input overvoltage protection	100V (continuously)

Software¶

SINTRAN supports up to 8 ND820 (64 channels).

The FORTRAN calling sequence is according to ISO (Perdue) standard:

CALL AIRD (INUM, ILDAR, IRSAR, IVAL).

INUM: Number of channels
ILDAR: Integer array containing the channel number (0–63)
IRSAR: Integer array where converted data will be stored
IVAL: Error indicator

The ND820 may be operated in the desired mode by initializing the A/D Converter using the monitor call IOSET.

IOX Instructions¶

Channel selection¶

IOX <set MUX channel>
A-register bits 0-2 select channel 0-7

Control word¶

IOX <load control word>
A-register:
Bit 0   Enable interrupt
Bit 1   Not used
Bit 2   Start conversion
Bit 3   Not used
Bit 4   Master Clear
Bit 5   Enable EXTERNAL Interrupt
Bit 6   Enable EXTERNAL start of conversion
Bit 7-15 Not used

Status word¶

IOX <read status>
A-register:
Bit 0   Interrupt enabled
Bit 1   Not used
Bit 2   Busy
Bit 3-4 Not used
Bit 5   EXTERNAL Interrupt enabled
Bit 6   EXTERNAL start of conversion enabled
Bit 7-15 Not used

Converted data¶

IOX <read data>
A-register:
Bit 0             LSB
Bit 1-10        | 2’s complement
Bit 11           MSB

Country	Contact Information
Norway	NORSK DATA A/S, Jerikoveien 20, Box 4 Lindeberg gård, OSLO 10, Tel. 02-391601, Tlx. 18661 nd no
Denmark	NORSK DATA ApS, Overdrevsvej 5, 2840 HOLTE, Tel. 02-425055, Tlx. 37725 ndk dk
West Germany	NORSK DATA DEUTSCHLAND, Abraham-Lincoln-Str. 30, 6200 WIESBADEN, Tel. 0611-264720, Tlx. 4186370 noda d
Sweden	ND NORSK DATA AB, Kanalvägen 3, Box 2031, 194 02 UPPLANDS VÄSBY, Tel. 0706-86050, Tlx. 13528 nordata s
France	NORSK DATA FRANCE, "Le Brévent", Avenue du Jura, 01210 FERNEY-VOLTAIRE, Tel. 050-408576, Tlx. 38563 nordata fernv
U.S.A.	NORSK DATA A. N. A., Inc., 65, William Street, Wellesley, MASS. 02181, Tel. 0617-237.7945, Tlx. 921740 norsk well
Sweden	ND NORSK DATA AB, Klangfärgsgatan 11, Box 9052, 421 09 VÄSTRA FRÖLUNDA, Tel. 031-299350
France	NORSK DATA FRANCE, 120, Bureaux de la Colline, 92213 SAINT-CLOUD-CEDEX, Tel. 01-6023366, Tlx. 201108 nd paris
England	RICHARD NORTON (NORD) Ltd., NORD House, 17 Balfe Street, King's Cross, LONDON N1 9EB, Tel. 01-2785501, Tlx. 299537 norton g

Note: NORSK DATA reserves the right to change specifications at any time without given notice.