Documentation

Real Time Devices DM7420 Analog Input (A/D)

DM7420 Analog Input block (not recommended)

Library

Simulink® Real-Time™ Library of Drivers No Longer Recommended for Use

Scaling Input to Output

Hardware Input

Block Output Data Type

Scaling

Volts

Double

1

Block Parameters

Channel vector

Enter numbers between 1 and 16. This driver allows the selection of individual A/D channels in arbitrary order. The number of elements defines the number of A/D channels used.

For example, to use the first, second, and fifth channels, enter

[1,2,5]

Number the channels beginning with 1 even if this board manufacturer starts numbering the channels with 0.

Range vector

Enter a range code for each of the channels in the channel vector. The range vector must be the same length as the channel vector. This board allows the range of each channel to be different.

The following table is a list of the ranges for this driver and the corresponding range codes.

Input Range (V)

Range Code

-10 to +10

-10

-5 to +5

-5

0 to +10

10

For example, if the first channel is -10 to +10 volts and the second channel is 0 to +10 volts, enter

[-10,10]
Gain vector

Enter 1, 2, 4, 8, 16, or 32 for each of the channels in the channel vector to choose the gain code of that channel. The gain vector must be the same length as the channel vector. This driver allows the gain of each channel to be different.

The following table is a list of the ranges for this driver given the gain entered in the gain vector.

Gain

Range (V)

1

0 to +10

2

0 to +5

4

0 to +2.5

8

0 to +1.25

16

0 to +0.625

32

0 to +0.312

Notice that by increasing the gain code the voltage range is decreased. The gain divides the input voltage range.

For example, if the first channel has a gain code of 1 (10 volt range) and the second and fifth channels have a gain code of 2 (5 volt range), enter

[1,2,2]
Input coupling vector

Enter either 1 (ground-referenced single-ended (RSE)), 2 (nonreferenced singled-ended (NRSE)), or 3 (differential (DIFF)) for each of the channels in the channel vector to choose the coupling code. The coupling vector must be the same length as the channel vector. This driver allows the coupling of each channel to be different.

The following table is a list of the couplings for this driver and the corresponding coupling codes.

Coupling

Coupling Code

Description

RSE

1

High side of input signal connected to the selected analog input channel. Low side of input signal connected to one of the analog ground (ANALOG GND) pins. See the board manual.

NRSE

2

High side of input signal connected to the selected analog input channel. Low side of the input signal connected to the analog input sense (AINSENSE) pin at the I/O connector. See the board manual.

DIFF

3

High side of input signal connected to the selected analog input channel AIN1+...AIN8+. Low side of input signal connected to AIN- pin corresponding to the AIN+. See the board manual.

For example, if the first and second channels are ground referenced single-ended and the third channel is a differential input, enter

[1,1,3]

For differential inputs, the driver selects a second differential input that is eight channels higher than the first channel. In the example above, the driver selects the eleventh channel (AIN11/AIN3-) as a differential input.

Sample time

Enter the base sample time or a multiple of the base sample time (-1 means sample time is inherited).

PCI slot (-1:autosearch)

If only one board of this type is in the target computer, enter -1 to locate the board.

If two or more boards of this type are in the target computer, enter the bus number and the PCI slot number of the board associated with this driver block. Use the format [BusNumber,SlotNumber].

To determine the bus number and the PCI slot number, type:

tg = slrt;
getPCIInfo(tg, 'installed')

Was this topic helpful?