The Impact of Windows, Handheld Technology on Data Logging
The huge impact of Microsoft Windows is not confined to applications running on the desktop PC. Today, Windows is also having a major impact on the world of instrumentation, transforming many devices from simple and inflexible monitoring tools into much more versatile reconfigurable products.
The real strength of Windows lies in its universal nature. Users already are quite familiar with its procedures, so learning curves on new equipment are drastically reduced.
On the hardware side, much recent technical advance has been on the back of portable or handheld instruments such as PCs, telephones and organizers. ICs are available which contain all the elements of a computer on one small chip - CPU, ROM, RAM, EEPROM analog to digital converter, serial port for communication to host computer and other I/O functions. Many, of course, even contain drivers for LCD readouts and the portable nature of the products means that IC manufacturers are moving towards products with a minimum of power consumption. Typically, years of battery life now can be obtained from a small button cell, depending on the mode of operation selected.
A new data logging family from Lascar Electronics in Savannah, Ga., known as EASYLOG takes advantage of both these hardware and software developments, by combining use of an NEC micro controller programmed in C++ but operating on a Windows platform.
Combining data logger and configuration software, the EASYLOG system is low cost and extremely easy to use to record a wide range of conditions such as temperature, humidity, pH, voltage and current. The type of input signal is selected in control software by the user during set up on the host PC. The correct signal conditioning, filtering and gain is then automatically selected by on-board electronic switches under the control of the CPU, switching off circuits not in use to conserve battery life.
The EASYLOG data logger is usually operated in a stand-alone condition, frequently monitoring indicators such as temperature for up to three years from one battery and capable of taking and storing up to 8,000 readings. On reconnection to the host PC, the data can be retrieved and processed in text or graphical form, easily integrated into Excel and a host of popular spreadsheet packages.
Alternatively, up to eight Easylogs can be daisy chained to cover a whole site, creating a complete environmental logging system running off the same serial port and in turn making an extremely powerful monitoring system. Display of the reading from all eight loggers can be displayed on the PCs monitor as a real time MIMIC PANEL. To avoid data loss in the event of battery failure, data points are all stored in EEPROM, a small serial device which will hold all 8,000 readings.
For large area sites and environmental loggers in remote locations, a modem interface version is also available. This allows EASYLOGs to be set up, interrogated and downloaded from any telephone line. Any user with a PC fitted with a MODEM and running EASYLOG software can then control a logger irrespective of location.
The EASYLOG product format is designed to provide the user with a significant degree of flexibility. Users can select between 8 or 12-bit resolution, dependent on measurement accuracy required. 8-bit will typically give 256 measurement steps with an average accuracy of 1 degree F or 0.1pH. The 12-bit version will give much higher levels of accuracy if required. Both versions also are available for either panel mounting or cased in a compact portable housing.
As the basic device is an advanced micro-computer, a user can also tailor the device to a specific application. Features such as variable sample rate between five seconds and 12 hours, delayed, automatic or press-to-start modes are all available. As in any sophisticated environmental monitoring system, many different alarm modes also are available. In France, one Lascar customer is using the product to monitor the pH level in a chemical solution. When set levels are exceeded, the EASYLOG sets off control circuitry to correct the imbalance. The whole process is continuously monitored and stored for future examination by health and safety experts.
In conclusion, the flexibility and low cost of these new generation products make them an ideal solution for a wide variety of logging applications, from process control to "due diligence" monitoring of refrigeration temperature and water quality logging. Products like EASYLOG take advantage of the latest hardware and software technology and design in the flexibility demanded across the environmental industry. It is these characteristics that will secure their continuing popularity in the data logging industry.