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Test Equipment Review Australian-designed Unimeter does it all If you have a workbench or workshop loaded down with test instruments, then you should seriously consider the Austra­lian-designed and built Autoplex Unimeter. It could eliminate a lot of clutter. Review by DARREN YATES The Unimeter is just as its name suggests – one instrument that can replace many of the single function pieces that clutter many benches. Not only can it auto-range measure AC and DC volts and current but it has over 100 other functions included which are selected by using the softkeys on the front panel. Some of these functions include metering for a variety of thermocouples, temperature meters for a number of IC sensors (including the LM35, AD592 and LM135), mains frequency meter, tachometer, period monitor, frequency monitor, up/down coun­ters, low-frequency sine and sawtooth generators, efficiency monitor and so on. Also available is optional software and a serial adaptor which allow you to feed data from the Unimeter to a standard PC. Thus, you can continuously monitor systems and save the data for later retrieval. You can also display the data graphically on screen for dynamic presentation and professional results. The software is menu driven and allows the user to The Unimeter is a multi-function instrument which interfaces with a PC to give on-screen displays of various measurements. Over 100 functions are accessible via the softkeys on the front panel. 80  Silicon Chip print out data and screen shots for hard copy storage. The Unimeter itself is very small, measuring just 150 x 91 x 44mm, and is designed to sit in a small instrument rack, the water and dustproof front membrane keeping the instrument free of foreign matter. Unlike many PC-interface instruments, the Unimet­er has a 4.5-digit liquid crystal display as well as the afore­mentioned softkeys. Programming Two comprehensive manuals explain how the device is programmed and also give programming examples on the RS232-RS485 data transfer protocol. Each function is explained with its own set of specifications so you know exactly what the Unimeter is capable of producing while working on that function. Easy to follow diagrams show how the front panel of the Unimeter is programmed, as well as how external devices such as the serial interface, flow meters, thermocouples and the LM35 temperature sensor are connected. Incidentally, an RS232-to-RS485 adaptor is also available, while mounting brackets and the hardware required are provided. Instructions on how to run the software are also included in the manual. This software is quite easy to use and very versatile, with on-screen graphical display of up to four variables available simul­ taneously. All inputs and outputs are connected to the back of the meter, leaving an uncluttered front panel which is easy to see and operate. Part of the design also includes the first QUADAC Quad-Slope Dual Referenced Bi-directional Conversion technique, which gives 14.5-bit conversion This screen capture shows the just four of the capabilities of the Unimeter (Function Generator, Rate Monitor, Process Meter & Linear Movement). Note that the display is normally in colour, thus giving a much more impressive readout than that shown here. but a resolution of 20 bits. This gives an overall accuracy of ±0.1% which is very good for an instrument of this type. Auto calibration is performed every 10 seconds to maintain this accuracy and ensure that measure­ments are spot-on. This is quite an amazing piece of gear when you consider that all of these functions come inside such a tiny package. It is ideal in most industrial control processes and represents a big step forward in wide-range data acquisition. One of the great things about the Unimeter is that it is designed and built in Australia and is distributed worldwide by Nilsen Instruments Pty Ltd. The cost of the Unimeter is $490 plus $400 for the optional software. Optional extras including a serial adaptor, a PLC interface and a power supply are also available (prices include sales tax). For further information, contact Allan Winford at Nilsen Instruments SC Pty Ltd, phone (03) 419 9999. November 1993  81