New submersible pressure and level sensors at IWEX 2012

The main focus of the stand will be how these sensors can communicate with process controllers, data loggers and telemetry stations, allowing easier integration with existing process control networks and fieldbuses. Controllers and their integral software programs provide users with archiving, printing and visualisation tools, as well as a variety of visual presentation display options for recorded measurements. Impress will also demonstrate how to set up PID profiles, timers, relays and triggers using these controllers. Using JAVA applets, which can be embedded into any website or HTML-based web page, users can remotely access real-time data from the controller via an Ethernet interface and web browser.

Also on the stand will be a number of submersible pressure, temperature and level sensors. The IMCTL (ceramic) and IMSTL (silicon) ranges of submersible dual output level and temperature transmitters, for example, are suitable for continuous submersion in water. These sensors provide dual independent, 2-wire, 4-20mA outputs: one for level and one for temperature. The sensors offer nominal pressure ranges from 10mWG to 100mWG (ceramic) and 0.5mWG to 100mWG (silicon).

The higher accuracy IMSTL version uses piezoresistive media-isolated silicon sensing technology and a stainless steel diaphragm. This provides excellent stability, repeatability and resolution, particularly for high-accuracy level and temperature measurement (including V-notch weir flow measurements) in rivers, canals, reservoirs, boreholes and aquifers.

A ceramic sensor for level measurements, which provides excellent corrosion resistance, particularly in aggressive media is used in the IMCTL. Applications include level and temperature measurements in tanks, rivers, boreholes and aquifers, as well as environmental monitoring in estuaries and seawater applications (when used with the marine bronze housing).

SDI-12 submersible hydrostatic level transmitters

Also on stand E48 will be the S12 range of submersible hydrostatic level transmitters, which offers an SDI-12 digital output with an inbuilt high-accuracy temperature sensor, which can be used in depths of up to 200m. This unit uses either a stainless steel silicon-based pressure sensor or a ceramic pressure sensor in marine-bronze. Both versions use piezoresistive technology, ensuring long-term stability and repeatability of measurements.

The stainless steel version offers a higher resolution of pressure measurement to around 12-13 Bit and has a much lower signal-to-noise ratio, providing a very smooth and accurate method of level measurement. The S12 is suitable for monitoring river and reservoir levels; tanks and vessels in process plants; seawater and estuary levels; borehole water levels; tsunami and tidal monitoring systems; wave height measurement; environmental monitoring; and V-notch weir flow measurement.

For marine use, where standard devices may suffer from corrosion, the ceramic pressure sensor version is the better option. These units are suitable for seawater, estuary and saline applications. There will also be demonstrations of the most recent release of Impress' configuration software, which enables easy set up and configuration of these devices, including offsets, reverse output, calibrating, density correction, local gravity adjustment and many more features. The software also has a data logging facility for locally data logging the sensors, which is particularly useful for fault finding and diagnosis of a site.

Visitors to stand E48 will also be able to see Impress' new IMTG series of submersible tank gauging level transmitters. This piezoresistive silicon pressure sensor is designed for continuous submersion in water, particularly in small (0-10m depth) water tanks or containers, where the use of conventional mechanical level switches is not ideal and more level "control' and measurement is required. Typical applications include the measurement of static tank levels, container or chamber levels and vehicle tank levels. A WRAS-approved version of the IMTG is also available for drinking water applications.

Multi-channel controllers

As well as submersible pressure and level transmitters, Impress' stand will also feature a full working demonstration of the company's compact, multi-channel, touch-screen range of controllers, including the CMC-99 and CMC-141. These controllers are suitable for the simultaneous measurement and control of a variety of water and wastewater applications, including intermediate pumping station measurement and control.

The CMC-141, for example, is a compact, multi-channel controller with large touchscreen colour TFT display and up to 72 digital inputs/outputs. The "big brother' of the CMC-99 controller, the CMC-141 provides all the same functionality and features, but offers a larger 5.7-inch backlit display, more inputs/outputs and new types of logic channels.

Both controllers have an auxiliary 24V DC/200mA supply output on the back, which enables external sensors and actuators to be connected and powered by the controller. The controllers can also act as PID process controllers, providing a reliable control loop feedback mechanism for a variety of water temperature and level control applications.

For more information on Impress Sensors' range of submersible pressure, temperature and level transmitters and other products, or for a sensor demonstration, please call in on stand E48 at IWEX 2012 or visit the website at www.impress-sensors.co.uk.