issue: September 2003 APPLIANCE Magazine Electronic Controls and Embedded Systems The Commercial Connection	Share  Printable format  Email this Article  Search
by Lisa Bonnema, Managing Editor In May 2003, Hobart Corporation (Troy, OH, U.S.) decided to take its foodservice equipment to the next level by adding communication capabilities.

To start, Hobart had to decide how it wanted to add the connectivity. According to Rick Cartwright, manager of Electrical Engineering and Advanced Development at Hobart, there are several ways a manufacturer can make its products NAFEM compliant. "One way is a bolt-on solution," he explains. "Suppose you're a manufacturer of equipment that incorporates very little electronic support or intelligence on board. You might buy a bolt-on solution that will give you the ability to support the protocol. You would attach this black box outside your machine, and it will have sensors and probes that attach to the target equipment, and provide data from your equipment to the network, and, of course, back to the house computer or some other host."

Hobart, however, chose another option. Because most of its appliances have advanced electronic controls, sensors for monitoring data points, and some communication capabilities already built in, it is using a gateway device from Watlow.

"This is an oversimplification, but think of a gateway as a protocol converter," explains Mr. Cartwright. "It converts data that is communicated from the Hobart control and makes it available on the network using the NAFEM protocol. It made sense for us to use a gateway because we already have all this communication in the system, and it's a fast and easy way to get into the market."

Specifically, Watlow is providing Hobart with its On-Line Kitchen Gateway. According to Leon McNutt, R&D manager of Control Technologies at Watlow, the gateway can interface with any piece of food equipment that has MODBUS RTU protocol connectivity. "The On-Line Kitchen Gateway uses a 32-bit microprocessor with FLASH memory, RS485 communication bus driver, real-time clock, and an Ethernet MAC PHY chip set to provide the connectivity at both the equipment and network sides and to provide the processing logic to perform the required functionality that NAFEM has proscribed for compliance devices," he says.

"Hobart's controller will provide the monitored data information to its MODBUS RTU interface, and the On-Line Kitchen Gateway will poll this interface and map the data into the NAFEM Data Protocol Objects defined by the MIBs [Management Information Base], thereby making this monitored data available to the kitchen network," Mr. McNutt continues.

The gateway is also capable of talking to up to eight pieces of equipment and can then tie all of them to the Ethernet bus. "So if you have a bank of eight refrigerators lined up relatively close together, you could tie all eight of these into one of these NAFEM gateways, and it will connect to your house computer or to the Internet," notes Mr. Cartwright of Hobart.

To fully enable its equipment, Hobart had to develop firmware to support Watlow's gateway. "Although our equipment already has software to manage, run, and operate the equipment and to provide the customer with immediate feedback on the display, we had to go a step further and communicate the proper data and the proper format to the gateway," Mr. Cartwright explains.

Hobart will initially offer the gateway on some of its refrigeration and warewashing appliances, although it plans to slowly add compliance to other product lines. Specifically, the company will launch its NAFEM-compliant blast chillers, LXi dishwashers, and G, R, and A series Traulsen refrigerators and freezers at the NAFEM trade show this month in New Orleans, LA, U.S.

Data Decisions

According to Mr. Cartwright, Hobart's NAFEM-compliant equipment can offer end users several benefits, including monitoring temperature settings, product inventory, energy utilization, and labor deployment.

At the restaurant chain level, a manager could, for example, instantly retrieve chilling and holding records from blast chillers and refrigerators throughout the chain. Data from all points of the kitchen operations would verify that standards were being followed. Managers could also monitor in real-time warewashers to ensure proper sanitizing temperatures or the supply of sanitizing chemicals. They could also improve the efficiency of how often and how much of a particular product or ingredient to order based on real-time product inventory. Benefits include greater food safety, product freshness, and the savings associated with just-in-time inventory.

One of Hobart's greatest challenges, then, was to decide just how much data„whether it be temperature, pressure, or serial number information„it wanted to offer its end users. "When you say you're NAFEM compliant, the protocol is not a one-size-fits-all situation. Everybody is going to use bits and pieces of protocol. You don't have to use all of it," notes Mr. Cartwright. "We were concerned about making sure that we knew how much data the customer wanted„what provided value to the end user. You could overwhelm a customer with data. For us, it was trying to make sure we didn't just provide them with data, but with a solution that could give them the flexibility to get the types of data that would make their job easier and more efficient."

Hobart also wanted to keep data points limited to offer its customers cost savings. "A gateway is only capable of handling a fixed number of data points," says Mr. Cartwright. "The problem is once you use all those up, you need additional gateways. There's an economic issue involved. So you'd like to be able to optimize that number [of data points] and make it as big as possible. "

To answer the data question, Hobart's marketing team met with some of its customers and attended industry presentations and determined what types of data points made sense for its foodservice users.

Current Capabilities

Although each product is different and can be customized, Hobart believes most of its customers will probably be most interested in monitoring temperature for food safety reasons as well preventative maintenance data.

The company's blast chiller, for example, can monitor temperature via its product probes. According to Mr. Cartwright, the monitoring process starts with Hobart's internal electronics, which have the ability to read analog values from a sensor that can measure temperature. "Coming from the front end, you have a sensor, which in this case is a thermistor, and then we feed that into an a-to-d converter and into a microcontroller," he explains. "On the other end, we have a display so that we can actually display that information to the customer. Then we have the serial port that goes out to allow this data to communicate to the Watlow gateway, which in turn is attached to the kitchen network and uses the NAFEM protocol to communicate data."

In the end, the equipment operator can access temperature information from the product probes as well as temperatures of the inside of the cavity or the coil for service reasons.

The Next Step

The key to making its compliant successful will be education, according to Mr. Cartwright. "From a protocol standpoint, the big challenge right now is just education„helping people understand what it can do for them and the benefits," he says. "It's a little different than some marketing scenarios because we have a few customers that really demanded and expected this, and then we're trying to go out to the masses and help them understand why these other folks wanted it and what it can do for them. It's not just for restaurant chains."

Although it is anxious to see how customers react to its products, Hobart already has design improvements in the works to offer end users even more options. "Our equipment has Flash memory, so you can flash them with updates. Ultimately, we want to be able to do that remotely," says Mr. Cartwright. "The protocol allows for that. We just have to work out the details. There's some challenges there that not everyone can see. It's not something that will be there at first, but it will be there quickly."

Designing advanced electronics is nothing new for Hobart. The manufacturer is used to doing its electronics design from the ground up, making its partnership with Watlow an exception to the way it typically designs its products.

"Although we use different companies to actually manufacture our circuit boards, we design and specify all of our sensors, controls, microprocessors, and write all the firmware. Using an outside resource for the gateway is a deviation for us," Mr. Cartwright says. "We felt like for the time constraints involvedƒit was advantageous for us to use a solution from a source that already had finished it. It was a much lower risk and much faster. We felt Watlow had the knowledge and the talent to support what we were trying to do."