Wireless Pump Control
For those who haven't seen one, the tank farm at a large winery consists of a vast array of stainless steel storage tanks holding millions of gallons of wine. With the goal of allowing staff to remotely control pumping operations during topping off and transfer storage of wine, management at one of Australia's largest wineries realized the need for a wireless pump control system.
Housing hundreds of steel tanks, many of which are 60 feet high and closely spaced together, the winery complex structure had the potential to cause RF propagation problems. In addition, the pumping system is not a fixed installation, but serviced by portable electrical pumps (using 3-phase 415V ac) coupled by flexible hoses to vertically mounted, insulated tanks. This type of environment would require a wireless solution to provide quality RF signal coverage of embedded pumps in the tank farm, overcome electrical noise and electromagnetic interference generated during switching, and resist weather and water.
KRS Electronic Systems (Melbourne, Australia) worked with the winery to devise a wireless solution that would operate in such an environment and allow for real-time data to be continuously analyzed by the wine makers in the blending and bottling processes to ensure full production. To address all the requirements of the winery, KRS' solution would have to allow for:
Wireless control of numerous mobile transfer pumps and centrifuges used in wine production and operational requirements;
Integration of the pump control system onto the winery's LAN using 802.11b via a main server PC terminal connecting to various wireless handheld pocket PCs;
Wireless pocket PC operation in all areas of the tank farm and storage area; and
Mounting of the main controller in the mobile pump's electrical 415 V ac starter box.
At the heart of the wireless pumping system (designed for the winery by KRS) is the KRS Pump Manager RF module, which employs the DPAC Airborne 802.11b transceiver and a micro-controller. The RF module communicates with the KRS Pump Manager pump control module via an RS-485 interface. Fixed within the pump starter box, the pump control module not only controls the pump, but also provides basic telemetry (including pump motor current, wine flow rate, pressure, and temperature) back to the winery WLAN (wireless local area network). It also logs every task performed by the server or PDAs with the date, time, and name of user as well as gathering other important use data. The controller also provides pump and signal strength feedback to make sure every pump is receiving power to maximize the production process and anticipate any down conditions on the line.
DPAC Airborne module enables wireless function of KRS Pump Manager.
Due to the harsh propagation environment at the winery, KRS designed a dual-polarized patch antenna, providing high gain, hemispherical coverage, and polarization diversity to combat fading. Status and signal strength LEDs on the controller allow for visual feedback of RF signal levels to the operator.
The wireless pump controller also supports additional functionality that the winery has not yet implemented, such as pump motor current sensing to determine if the pump motor is operating under safe load conditions. Phase drop out can also be detected to protect the pump motor. Temperature sensors can be used to determine wine temperature and pump seal temperature. To estimate the wine tank volume transfer, flow sensors are available.
Because RF signal levels could not be guaranteed within the tank farm areas due to the environment, KRS suggested a propagation test, resulting in the placement of a number of fixed high gain antennas to provide the required signal strengths. In addition to the high-gain antennas, the KRS Pump Manager hardware is designed in two modules linked by an RS-485 full duplex 30-ft cable, which allows for flexibility in positioning the RF control unit to achieve maximum signal strengths when placed in the tank farm.
Prior to installation of the KRS Pump Manager system, 50 full-time winery personnel working on rotating shifts were needed to handle pumping at peak bottling time. With the new controller, the winery can now redeploy half of this staff to work in other areas such as pump connection, tank preparation and maintenance, centrifugal operation, refrigeration control and other vital work in processing wine.
For more information, visit:
KRS Electronic Systems www.krs-systems.com