USB data acquisition unit features eight single ended or four differential analogue inputs, two analogue outputs, 20 digital I/O including a 32 bit counter and watchdog timer
A powerful but low-cost data logging solution is now available from Audon Electronics in the form of the LabJack U12 USB DAQ unit and the Davlogger datalogging software.
The Labjack U12 features eight single ended or four differential analogue inputs, two analogue outputs, 20 digital I/O including a 32 bit counter and watchdog timer, all for under £100.
Single ended channels have a +/-10V input range while differential channels take advantage of a low noise precision amplifier with gains of 1, 2, 4, 8, 16, 20.
In addition, Audon Electronics can supply temperature and humidity sensors that can be directly connected to the LabJack, and thermocouples can be accommodated with the use of the TCA-4 thermocouple amplifier.
No external PSU is required, as the LabJack and all accessories are powered from the USB port.
Up to 80 LabJacks can be connected to a single PC to increase channel capacity with the use of USB hubs.
Davlogger is a powerful but low-cost datalogging software package for use with the LabJack.
The DAV Datalogger application allows you to store up to 150 channels of data onto disk and directly into a Microsoft Excel spreadsheet and play back the data at a later date.
In addition, Davlogger can display data in a notepad-style listing window and also a chart recorder display in real time. Each analogue input channel can be scaled into engineering units, can be added to the chart display with a choice of line colour and can be assigned an upper and lower alarm limit.
Alarms can be used to set LabJack digital outputs and with the use of the RO-16 relay expansion board can be used to switch heaters and pumps on and off, and provide basic control functions.
The alarm function can also be used to help reduce the size of log files.
There are two user selectable log rates - normal rate, and alarm rate. Normal rate is the speed at which the data logger normally runs. Alarm rate is the speed at which data is collected when an alarm limit is passed in any channel that has an alarm set up.
This rate will continue until all channels are within their alarm limits.
Hence by selecting a slow normal log rate and a faster alarm log rate, data file size can be minimised, but it is still possible to record important data at full time resolution. Logging can be started and stopped manually or automatically at preset start/stop date/times - useful for unattended operation. Data is stored in a time-stamped CSV format.
Davlogger also supports DDE, and can place data directly into Excel spreadsheet cells in real time, automatically incrementing the channel row as it goes.
