Rugged battery powered wireless level sensor

Paul Boughton

The Deeter Group has launched its  Wireless Sensor System for industrial measurement and control.

At the centre of the Deeter Wireless Sensor System is the simple-to-use Base Station designed to receive data from remote wireless devices such as the Deeter Liquid Vertical Sensor (LVCS-RF).

The base station converts remote sensor input signals into industry standard process outputs. The Base Station acts as the coordinator for an IEEE 802.15.4 wireless sensor network. It operates on one of 16 radio frequency channels available in the 2.4GHz ISM band.

The high power transceiver can achieve a range of greater than 1km, subject to local environmental factors.

The internationally recognised IEEE 802.15.4 protocol allows several wireless sensor networks to share the same wireless spectrum without interference.

The Base Station provides four open-collector transistor outputs which may be used to drive external relays for pumps and alarms or Deeter’s Dual Level Controller. Continuous analogue sensor data such as liquid level is output using a 4-to-20mA current-loop driver which enables interfacing with industrial process controllers or the Deeter Group’s range of Current Loop Indicators. A serial communications channel provides full-duplex RS232 and half-duplex RS485 transceivers allowing software to be developed for linking to PCs, data-loggers, PLCs or other proprietary equipment.

The Base Station has three internal push-button switches and a 2-line by 16-character LCD. The buttons are accessible with the lid removed and are used in conjunction with the display to select installation options during initial setup. Once the system has been installed it will continue to operate without any further need for user intervention. The Base Station is housed in a rugged ABS enclosure with an external antenna. It has cable glands for power input and signal outputs and is supplied with an external, wall mounted, universal AC input power supply.

Deeter is launching the wireless Base Station with the Liquid Vertical Continuous Sensor - Radio Frequency (LVCS-RF) wireless sensor. The LVCS-RF is designed to measure a continuous liquid level and transmit this information by radio to a Deeter Wireless Base Station at regular intervals. The device is battery powered and transmits wireless sensor data using the IEEE802.15.4 protocol operating in the 2.4GHz frequency band. The  transmission range is up to 1Km in ideal line-of-sight conditions. The operating temperature range is -20 to 70ºC.

The LVCS-RF circuitry is housed in an IP65 rated die-cast Aluminium head with an external antenna. An optional 3m extension lead and bracket are available for mounting the antenna in a position more favourable to wireless communication should the need arise. The sensor circuit is fitted inside a Food Industry Standard 316L stainless steel tube attached to the head, with a 55mm magnetic ball-float. Standard sensing lengths are 250mm, 500mm, 750mm and 1m. Custom lengths and materials are available on request. The LVCS-RF is powered by a single 3.6V Lithium Thionyl Chloride battery with a life typically of nine months (based on a transmission interval of 10 seconds and an uninterrupted wireless link to the base station).

For more information, visit www.deeter.co.uk