Wireless is helping with level monitoring in pharmaceutical tank level application in an intrinsically safe area, in a wastewater application to avoid overflow, and to monitor a rural water supply. Implementation advice that follows from these applications could help with your next wireless application.

A pharmaceutical manufacturer of plasma products, CSL Behring, improved safety issues, met compliance regulations, and increased data access and availability for better decision making using wireless technology.

“Wireless transmitters allow us to monitor our tanks on a real-time basis rather than an operator hand measuring the tank levels once a day. We can now make a much better inventory of our process liquids,” says Jeff Dabney, senior process engineer at CSL Behring. The application uses Honeywell XYR 5000 wireless transmitters, which enabled CSL to:

• Improve employee safety by eliminating manual level monitoring;
• Reduce vapor emission into the environment;
• Avoid prohibitive wiring costs and reduce installation, operational and maintenance costs;
• Increase reliability and data accuracy to meet and maintain regulatory compliance; and
• Provide more timely, consistent, and accurate measurements.

CSL Behring's line of therapies include products for the treatment of hemophilia and other coagulation disorders, immunoglobulins for the prevention and treatment of immune disorders, treatments that inhibit the formation of blood clots, wound-healing agents used during major surgical procedures, and plasma expanders for the treatment of conditions such as shock, burns, and circulatory disorders. CSL Behring employs more than 6,000 people in 18 countries.

CSL's alcohol tanks sit outside rather than in an enclosed area. Employees had to walk up narrow stairways to the tops of the 50-year-old, 10,000-gallon storage tanks, which stand about 15-ft high. “We have employees walking out to these tanks in the rain and snow and whatever else,” says Jeff Dabney, senior process engineer at CSL Behring's Kankakee, IL, facility.

Manual level checking of tanks with intense alcohol concentrations present safety risks for employee exposure and of explosion. Eliminating manual checking reduces risk, but “We had a big challenge finding a level measuring system to run into our Class 1 Div. 1 area that did not involve thousands of dollars in intrinsic barriers alone,” Dabney says. Since the application was outside, crossing several roads, “trenching was out of the question, and large trucks are used, so this would mean a large expense in putting up an overhead conduit system. The costs of wiring prevented us from doing the project for a long time. Running 300 feet or 400 feet of cable or conduit would have been cost prohibitive,” Dabney says. The wireless base now sits about 300 yards away from the storage tanks next to a cooling tower on the facility campus.

Pressure transmitters sensing the weight of the alcohol in the tanks send data to the wireless base, which transmits numbers to a programmable logic controller. Employees can view the data any time on a computer screen versus manually checking levels.

Also, the wireless transmitters enable the company to emit even less alcoholic vapors into the air because workers no longer have to physically open the tanks to take measurements.

A thorough site survey is needed, Dabney advises, when choosing the location of the base unit, anticipating changes over time.

“We had a cooling tower between the base unit and the sensors that was inactive when we started the install in early spring,” he says. “As the weather warmed up and the cooling tower was turned on, our signal strength was a real problem. We moved the base unit to a true line of site arrangement and have not had any issues since,” Dabney says.

Avoiding sewage overflow, aside from being a safety, environmental, and public relations necessity, is good business for JEA, the municipality utilities provider for Jacksonville, FL. Sewer access areas, manholes, are a harsh Class 1 Div. 1 environment. JEA, after investing in a robust SCADA system to control and monitor more than 1,200 lift stations, needed a monitoring system to get information from the sewer manhole to the SCADA system. The system was needed to monitor the manhole and give JEA time to repair infrastructure.

After field tests and evaluations for signal strength and durability, JEA chose Weidmuller wireless technology for reliability and company support. (Many devices and suggested solutions failed the test.) The manhole monitoring system has been used in 17 manholes, preventing four sanitary sewer overflows (SSO).

Under cover, the radio transmitters needed a signal strong enough to get out of a sewer manhole, through a steel plate cover, withstand the harsh environment of a sewer manhole, be intrinsically safe, and operate with a battery. It also had to be portable so it could be moved where needed after infrastructure improvements, and operate with JEA's existing SCADA system.

The Weidmuller device was said to be the only one evaluated that met all of JEA's requirements. Programming was a free download and easy to use and understand, JEA says.

The local distributor was directly involved in the field tests, and packaged the Weidmuller radio system, enclosure, terminals, and equipment needed to meet application requirements.

The program gave JEA the ability to control transmission of signals and prolong battery life.

MTS Systems Corp. Sensors Division provides a Web-based tank monitoring solution it developed with OleumTech Corp. (Irvine, CA) to assist with water supply monitoring for a residence in Pie Town, NM, where owners needed an easier, more accurate way of monitoring the water level in a 3,000 gallon tank. The system makes more efficient use of the water supply and allows more cost-efficient delivery.

MTS Sensors uses its Level Plus model MG liquid level transmitter to measure the level in the storage tank. The tank level is transmitted via Modbus to the OleumTech LevelMate Monitor, through trees and three walls, sending the measurement to the house where the OleumTech DataHub is located. DataHub output connects a fieldbus controller that places the information on the Internet. Users can open the Website and poll the unit to find out the last collected measurement and customize the update time of the radios and the Web interface.

“The wireless system makes it possible for us to accurately determine the available water from the comfort of our home 150 feet from the tank,” says Anne Dorough, resident owner. “My husband's visual impairment made it impossible for him to estimate the water level, and he was worried about my climbing that hill in inclement weather. We both really appreciate what MTS and OleumTech have done.”

The couple's isolated location requires that their water supply be delivered by truck, and the new system allows them to monitor for leaks, schedule deliveries to get the best pricing, and better manage appliances that affect their water supply.

The system is convenient, safe, and more accurate than manual measurements.

The MG transmitter can provide 3-in-1 measurement of product level, interface level, and temperature, with high accuracy, reliability, simple installation, and field replacement. Lengths range from 508 mm (20 in.) to 18,288 mm (720 in.) It operates on 12 or 24 V dc power via 4-wire Modbus connection.

– Application stories here and online were secured by Control Engineering's Peter Welander and edited by Mark T. Hoske.