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