“We have hundreds of vessels inside our breweries, which are fully automated, so we don’t have any people walking around to monitor things,” said Paul Metzger, Anheuser Busch senior process engineer, brewing engineering and technology instrumentation. “We operate 12 breweries in the U.S., 14 in China and one in the U.K. We demand 110% performance 100% of the time.”
And when you combine hundreds of stainless-steel tanks and 8,000 measurement points with a brewery’s solid floors and walls, you might think the environment presents a significant challenge to obtaining reliable wireless measurement signals. Yet starting in 2007, the company embarked on a journey to test wireless for applications in its operations around the world.
“We put a transmitter inside a vessel and a gateway inside a stainless-steel cabinet, and we still had reliable data.” Anheuser Busch’s Paul Metzger put Emerson’s Smart Wireless architecture through extensive performance testing. “Even our IT department was very impressed.”
Metzger presented an update of his company’s wireless initiatives at the 2008 Emerson Global Users Exchange this week in Washington, D.C.
“We get to do alpha and beta testing of new technologies from Emerson,” Metzger explained. “And in 2007, we installed a 900-MHz wireless network to determine its robustness in the brewery. Our IT department said, ‘At 900 MHz, you’re not in our range,’ so we didn’t have to deal with IT approval for our networks.”
The potential glitch came with the change to the 2.4-GHz range. “The IT guys slammed the brakes on us and required testing to address coexistence issues,” said Metzger. Additionally, Metzger’s group also needed to interface the Rosemount 1420 gateways with Rockwell PLCs on the machines. But the first step was in validating network reliability.
“We created a 10-transmitter network in our engineering building to validate network reliability between floors by using signal-strength and path-reliability data,” said Metzger. “We put several transmitters on different floors and created pinch points to evaluate performance of range and put a lot of information through them for six weeks, and we still had no packets dropped. We did everything we could to try to weaken the network performance, but we had to go to extremes to test it.”
Anheuser-Busch also validated coexistence of the 2.4-GHz system with the existing 802.11 networks. “Even our IT department was very impressed,” said Metzger.
One issue Anheuser-Busch needed to address initially, and has asked Emerson Process Management to address in the long term, was interfacing the gateways with Rockwell PLCs using the Modbus protocol for communications. “For the interface, we chose the Modbus protocol off the gateway because it was the easiest thing to attach and connect directly, but that required a third-party module, so we chose a ProSoft card to interface,” explained Metzger. “Emerson is working on something for us now to help get rid of this third-party card.”
Hundreds of Monitoring Points
Once Metzger and his group got down to the points they wanted to monitor, the transmitters stepped up to the challenge. “The wireless instrumentation has proven to simplify implementation of hundreds of potential monitoring points in the brewery,” he said. “We had additional measurement opportunities on mobile equipment skids and critical hardware. The self-organizing network that we installed has a primary path and then a secondary path through another transmitter to get the data back to the gateway to ensure reliability.”
Transmitters were placed in brewery vessels that are 25 ft in diameter. “Early in our brewing process, we hydrate grain to start the enzymatic activities in the grains and remove the sugars,” explained Metzger. “We need the simple sugars for fermentation. On this piece of equipment, occasionally an arm inside it fails and requires us to shut down the entire line. We wanted to put the transmitter inside the stainless-steel vessel on the arm to give us an up-or-down position. The transmitter had to be able to withstand the environment. We put the transmitter inside the vessel and the gateway inside a stainless-steel cabinet, and we still had reliable data.”
Anheuser-Busch also has put the wireless temperature transmitters on modular and portable skids that contain some of its yeast strains. “We can’t let our yeast become hybridized with other yeast,” explained Metzger. “We overnight these tanks to our breweries. We’ve configured two gateways 600 miles apart so the transmitters can sync up.”
In addition, vibration monitors were installed on tanks for clean-in-place validation. “We’re fully automated,” reiterated Metzger. “No one is out there to verify the tanks are being cleaned. We installed the monitor to feel the vibration of the jets every time they came around to clean the tank. We installed this and had it up and running in about 25 minutes.”