Specifications for Model 302
USB-Interfaced 24-Bit Data Acquisition System

 
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Documentation
User Sample Applications
Developer's Samples w/SourceCode
Only installation files and utilities


OVERVIEW
The Model 302 is a complete, Delta-Sigma high-resolution data acquisition system for the Universal Serial Bus (USB). It serves as a general purpose A/D converter or as a built-in interface for a wide variety of instrumentation. Up to 32 Model 302s can be connected to a single USB port using inexpensive hubs. Six analog input channels are provided, along with four digital inputs and eight digital outputs.

Lawson Labs has been designing and building high-resolution Delta-Sigma Data Acquisition Systems since 1991. The Model 302 represents our sixth generation of Delta-Sigma design. It incorporates the optical isolation and input protection that have long allowed our high resolution systems to function reliably in the industrial environment.

The analog input range is +/- 5 volts, true differential. The maximum single-channel data rate is 1000 Hz at 20 bits effective resolution. Two channels can be scanned at 100 Hz with effective resolution of 20 bits. As the unit is slowed down, it quickly gains effective bits to 22 bits at 200 Hz and 22.5 at 50 Hz for single-channel operation. The input impedance is 10^13 and the DC common mode rejection is typically -100 dB. The isolated portion of the Model 302 operates from a single unregulated, low-power supply.

Drivers are provided for Win98/ME/2k/XP/NT, with VC, VB, and LabView® sample application code. The VB sample code includes a real-time graphic presentation of single-channel scanning data, and is powerful enough for many general-purpose data logging applications. Multiple A/Ds can be split between 32 applications, or all used by one, or anything in between. Units can be connected or disconnected on the fly, without interrupting other ongoing acquisition. In order to obtain fully independent operation, even under fault conditions, we found it beneficial to write our own low level USB device drivers. These drivers should provide high-reliability operation for critical acquisition tasks.



SPECIFICATIONS
A/D TYPE
24-bit delta-sigma converter with microcontroller supervisor and optical isolation.

MONOTONICITY
23 bits

LINEARITY
+/-0.002% of full scale.

DIFFERENTIAL INPUT RANGE
+/-5 volts

DC COMMON MODE RANGE
+/-6.5 volts

DC COMMON MODE REJECTION
-100 dB typical

DIFFERENTIAL ANALOG INPUT CHANNELS
6 Multiplexed true differential protected to +/-60 volts.

ANALOG OUTPUTS
3 at 14-bit resolution, settling to 99% of full scale in 1 second.

INPUT IMPEDANCE
10^13 ohms typical

PROGRAMMABLE DATA RATE
50 to 1000 Hz, lower rates are generated through digital averaging.

EFFECTIVE RESOLUTION
Effective resolution is defined as total resolution in bits minus RMS noise in bits. Figures below use an oversampling ratio of four. 
Rate    Effective Resolution in Bits 
-----------------------------------------------                              
1000                                    20			
 500                                     21			
 200                                     22			
   50                                     22.5
SCANNING MODE
Three scan types are available, single channel, multi-channel, and a calibration scan that adds a reading of the zero channel at the end of each scan for offset drift compensation. The max number of data points per second in multi-channel scanning mode is 200. Any of the three scan types can add a digital input into the data stream after each conversion. That feature allows maximum timing accuracy for digital events.

DIGITAL INPUTS
4, contact closure or 5 volt logic compatible.

DIGITAL OUTPUTS
8 latched, ruggedized, double-buffered 5V outputs.

POWER REQUIREMENT
11 to 15 VDC, regulated or unregulated, for isolated circuitry or 15 to 30 VDC with pre-regulator option

TYPICAL POWER CONSUMPTION
The microcontroller operates as a low-power USB bus-powered device. The analog input and digital I/O requires 25 MA (add drive current for active digital outputs, up to 20 MA each).

SIZE
6.5 x 4.8 x 0.8 inches

OPTIONS
USB cable with bulkhead mount Type B connector (Normal USB cable is included in standard price.)
No standard enclosure is available at this time

CONNECTOR
All input and output (except USB) is via screw terminals on 0.2 inch centers

PRICE
$450.00 including wall-mount power supply.



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Download Files only needed for installation
( Driver, DLL, .INI, .INF, documentation )
Win/98/ME
archive     individual files
Win/XP/2k/NT
archive     individual files
Download Misc Documentation
Win/98/ME
individual files
Win/XP/2k/NT
individual files only    
Download Developer's API documentation
Win/XP/2k/NT
archive     open in browser




























































 
documentation
User Manual
Installation
LL_USB.INI usage
Troubleshooting




























































 

User Manual view online       ( click link to view manual in your browser window ) archive       ( click link to download manual archive to your PC disk drive )
Specs and Usage

The user manual is a compilation of operating instructions and specifications and the place that we always recommend that you look first concerning questions related to the Model302





























































 

Installation click  HERE  to view installation instructions in your web browser
click  HERE  to download installation instructions to your PC
Installation instructions are provided to help get you up and running very quickly. The instructions provide you with step by step procedure to follow along with troubleshooting information just in case you may encounter any difficulty when installing the Model302 USB devices





























































 

Troubleshooting  HERE   for   troubleshooting  information       ( click link to view in your browser window )
This document is the place to turn for any question concerning trouble that may be encountered when installing or interracting with the Model302 or related software. We make an attempt to keep this document updated as we learn of new problems that may be encountered when dealing with our USB devices. The troubleshooting covers things such as failure to connect, management of memory buffers, errors associated with loss of power and power spikes, and more. Please read this document before contacting us for problems you may encounter that may be related to these topics.





























































 

LL_USB.INI click  HERE  to view troubleshooting information in your web browser
click  HERE  to download troubleshooting information to your PC
We provide a special configuration file in .ini format in order to simplify various operational aspects and communication between the Model302, DLL, and final user application. This configuration file contains settings that enable you to boost both driver and DLL performance, as well as log error information to a disk file if you should encounter problems while interracting with the DLL. The log files are referred to by us as "debug information" and are a very useful tool if you should encounter problems and would like to convey those problems with us.





























































 

Sample applications
Fully functional applications. These are sample application provided to demonstrate the functionality of the Model302 devices. Various interfaces are available as a result of the programming languages used to develop each.





























































 

Developer Samples w/SourceCode
Multi-functional    ( created prior to 3-8-05 )
Fully functional applications with code included. These are rather large multi-functional application examples designed to demonstrate the way in which the many functions of the Model302 work together. These are written in various languages such as VisualBasic, VisualC++, LabView, and others.

Newest simplified mini    ( created after to 3-8-05 )
Fully functional "mini" applications with source code to help developers interract with only a minimum number of functions at a time. Samples and source code are available in C/C++, VisualBasic, and Labview environments.

Includes all documentation and installation files.





























































 

Version checker
This utility was created to reduce the possibility of confusion that can result from using a copy of the DLL that does not go with a particular version of the driver. Such a situation could happen if for example a new copy of the device driver is installed while not also installing the version of the DLL that is typically supplied with it in an archive or distribution source. A driver/DLL mismatch can also occur if old copies of the DLL find their way into various folders on your disk drive which may be searched by the windows loader prior to the location where you may have placed a newer copy, thus causing an older copy to load with the application while you may think that the most recent one is loading.





























































 
Installation files for your version of Windows  ( everything for making an installation diskette )
Win/98/ME archive     individual files
Win/XP/2k/NT archive     individual files

Version checker
This utility was created to reduce the possibility of confusion that can result from using a copy of the DLL that does not go with a particular version of the driver. Such a situation could happen if for example a new copy of the device driver is installed while not also installing the version of the DLL that is typically supplied with it in an archive or distribution source. A driver/DLL mismatch can also occur if old copies of the DLL find their way into various folders on your disk drive which may be searched by the windows loader prior to the location where you may have placed a newer copy, thus causing an older copy to load with the application while you may think that the most recent one is loading.



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