Multifunction USB DAQ Unit is Cheap but Fast

The U120816 is a very low cost USB data acquisition module which provides eight single-ended 12-bit analogue inputs, 16 digital I/O lines, two programmable pulse-width output channels, and one 16-bit counter channel. Analogue sampling rate is 32 ksamples/s maximum, with up to 13 ksamples/s for all 8 channels.

There are 8 single ended analogue input channels with an input range of 0-4.096V, 12 bit, so the resolution would be 1mv. The U120816 supports scan and streaming modes for data acquisition. The user can scan a single channel or scan multi-channels at once. In scan mode, the execution time is 8ms or 125Hz per channel. In streaming mode, the U120816 can start streaming data to the PC immediately or upon external trigger input, select through software. In trigger mode, a high state on the trigger line will start the data acquisition. The maximum throughput of streaming data varies with number of channels and they are also system dependant. Typically this is up to 32Ksamples/s for a single channel and 13Ksamples/s for all 8 channels.

There are 16 bi-directional digital I/O lines in U120816 module. Each line is software configurable to be either input or output high or output low. At power-up or reset, all lines are set to be input by default. All digital lines are 5V TTL and include a 470 ohm series resistor to provides over voltage/short-circuit protection. Each channel also has a 1M resistor connected to ground.

Thre is an external trigger line for streaming mode data acquisition. It is software configurable if the user wants to wait for this line. When in use, as soon as the line goes high, the device will start hardware timed data acquisition. This is a TTL level input.

There are two 10-bit PWM outputs in U120816. Software can set the period and duty cycle for each channel separately. The period is between 3 micro seconds to 333 micro seconds or the frequency is 333kHz to 3kHz. Duty cycle can be set between 0 – 100%. The PWM outputs can be used to light LEDs, drive motors, or convert to analogue outputs by adding an extra circuit.

The U120816 has a 16-bit counter. Software has the option to select if the counter should be reset after the read or not. The counter is incremented when it detects a falling edge followed by a rising edge. If you reset the counter while your signal is low, you will not get the first count until it goes high-low-high again.

The U120816 is supplied with the free application iDAQTest&Log. This package that can be used to test the U120816 device and log analogue input data and read back logged data for basic analysis. With this software, the user can browse through all the features in U120816, such as read single analogue channel, multiple analogue channels, streaming analogue input data continuously for display and log into file with or without external trigger, set DIO directions and read/write DIO states, set PWM output, read counter etc.

The U120816 also comes with a programming API iUSBDAQ.dll. This DLL can be called by third party applications. Programming examples are supplied in VB , ActiveX , dot net , C/C++ , Delphi, MacOSX. There is also a LabVIEW VI and program examples. Price for the U120816 is only £79

USB DAQ Unit has Flexible I/O

Available from Audon Electronics is the LabJack U3 low-cost USB multifunction data acquisition and control device. The U3 has 16 "flexible" inputs which can be configured for any mix and analogue, digital input or digital output making for a very versatile general purpose DAQ unit. The U3 is supplied with a wide range of FREE Data logging software and examples for use with most programming and DAQ packages.

The LabJack U3 can have up to 16 analogue inputs available on the flexible I/O lines. Single-ended measurements can be taken of any line compared to ground, or differential measurements can be taken of any line to any other line. Analogue input resolution is 12-bits with an input range of 0-2.4 volts. Optional signal conditioning adaptors are available that can condition the inputs to 0-5V, 0-10V or 4-20mA.

The LabJack U3 can have up to 20 digital I/O channels. 16 are available from the flexible I/O lines, and 4 are dedicated digital I/O. Each digital line can be individually configured as input, output-high, or output-low. The digital I/O use 3.3 volt logic and are 5 volt tolerant. Up to 2 flexible I/O lines can be configured as timers. The timers are very flexible, providing options such as Pulse Width Modulated output, pulse timing, pulse counting, and quadrature input from encoders. Up to 2 flexible I/O lines can be configured as 32-bit counters.

The LabJack U3 also has 1 or 2 dedicated analogue outputs which can be set to provide an output voltage between 0 and 5 volts with 8-bits of resolution.

The LabJack U3 is supplied with a range of free software. The LabJack Control Panel application handles configuration and testing of the U3. When first opened it searches for connected LabJacks and displays a panel whereby all the I/O types can be configured. The application also displays analogue/digital inputs and has boxes to set analogue/digital outputs. The U3 has field upgradeable flash memory. The self-upgrade application programs the latest firmware into the processor. FREE firmware upgrade will be available from time to time bringing improved performance and new features.

The U3 is also supplied with a copy of DAQFactory Express data acquisition and control, software. DAQFactory Express offers data logging, user designable screens with trending, automation capabilities and more. The U3 is also supported by the RealView Chart recorder software and the ProfiLab-Express programming package.

For programmers, the U3 is supplied with Visual C and Visual Basic modules for the LabJackUD driver, and simple example projects. A LabVIEW VI is also supplied.

The U3 is rugged and is designed for industrial use: the operating temperature range is -40°C to + 85°C and all I/O are overload and short-circuit protected. The ABS enclosure has screw mounting attachments and optional DIN rail mounting clips.

Available ex-stock from Audon Electronics for £69

The USB myPCLab DAQ Units has Universal Inputs

Available from Audon Electronics is the myPCLab USB
data acquisition unit which accepts thermocouples, PT100
temperature probes, Volts and 4-2OmA loops all for under
£60.



myPCLab is a very compact Data Acquisition tool which connects
to a PC via a USB port and monitors two universal analogue inputs,
accepting thermocouples, Ptl 00, Voltages and 4-2OmA current
loops along with one digital input. Sampling rate can be up to 128
samples per second and ADC resolution is user adjustable from
11 to 15 bits. There is built-in thermocouple and P11 00 linearisation
and automatic thermocouple cold-junction compensation.

The myPCLab comes with an intuitive and easy-to-use Windows
data logger software package which plots data, shows gauges,
bargraphs and digital readouts and logs data to disk. Logged data
can be exported in multiple file formats (xis, pdf, rtf, xml, html,dbf,
txt, csv) for easy importation to analysis and Spreadsheet packages.

The myPCLab software can simultaneously communicate with multiple
modules, making it easy to expand the number of inputs of a
measurement system.



Although the myPClab is USB based, it actually uses a virtual RS232
Com port, so any software package that can talk to a Corn port can
communicate with the myPClab. There are two communications
modes, ASCII text and Modbus.

With ASCII text Auto-send, data is transmitted from the myPClab
in a simple comma separated ASCII text format at a pre-set time
interval. Data can be read using any package capable of accepting
ASCII strings including most daq packages such as LabVIEW, VEE,
DAoFactory, TestPoint etc, programming languages VB, Delphi,
C++ .NET, and terminal programs such as HyperTerminal.

In MODBUS RTU Slave mode, myPCLab acts as a Modbus RTU
slave that can answer to Read Holding Register requests, Modbus
command number 3. The module doesn t have a specific Modbus
address, since it s the only device in its serial port. It will answer to
read request to any valid slave address. It can therefore be used
with every SCADA software package that support MODBUS RTU.

For more information, please contact :-

Audon Electronics
123 High Road, Chilwell, Nottingham NG9 4AT. UK
Tel: +44 (0)115 925 8412
Fax +44 (0) 115 925 9757
Web: www.audon.co.uk

LabJack U12 USB DAQ Unit

Now available in the UK from Audon Electronics is the LabJack U12 USB data acquisition and control unit.

The Labjack features 8 single ended or 4 differential analogue inputs,
2 analogue outputs, 20 digital I/O including a 32 bit counter and
watchdog timer. This is all crammed into a sturdy unit measuring only
150mm x 110mm x 35mm. 

The LabJack has a ±10V input range at 12-bit resolution. Differential
channels can make use of the low noise precision amplifier with gains
of 1,2,4,8,16,20, giving an effective resolution of greater than 16-bits.
Data can be streamed to disk at 1kHz and a bursts mode allows over
4000 samples to de taken at a 8kHz rate. The two 0-10V analogue
output channels can be updated at a 50Hz rate with 10-bit resolution.
All analogue I/O are accessed via screw terminals.

The LabJack has 20 digital I/O channels which can be individually
configured as input or output. Four digital I/O's are accessed via
screw terminals whilst the remaining 16 are accessed through a
25-way D connector; an optional relay/opto-isolator expansion
board is available.There is also one 32-bit counter available on
the LabJack U12, capable of counting frequencies up to 1 MHz. 
The LabJack U12 also has a watchdog timer function available
which can change the states of digital I/O if the LabJack does not
successfully communicate with the PC within a specified time-out
period. This function could be used to reboot the PC allowing for
reliable unattended operation.

The use of the PC's USB port allows for a simple plug-and-play
installation process and by using USB hubs, up to 80 LabJacks
may be connected to a single USB port.

Included with the LabJack are the free example applications
LJlogger and LJscope. LJlogger provides datalogger type
functionality. It reads all inputs, controls all outputs, writes real
time data to the Internet or hard disk, and sends email when
events are triggered. LJscope is a virtual oscilloscope program
with FFT display.

Drivers are provided as a DLL which can be called from most
programming languages. Also included are an ActiveX wrapper
and LabVIEW VIs which call all the functions in the DLL.