New generation valves - taking the risk out of fieldbus

Citation

(1999), "New generation valves - taking the risk out of fieldbus", Assembly Automation, Vol. 19 No. 4. https://doi.org/10.1108/aa.1999.03319dad.005

New generation valves - taking the risk out of fieldbus

Keywords Fieldbus, Pneumatics

Two industry firsts have been incorporated in a single product to be launched by Norgren at Hanover Fair in April.

The "intelligent" valves, which warn operators of impending failure can communicate with the four major fieldbus protocols.

The valves mark the next step in pneumatic technology. For the first time, valves are able to send messages to a fieldbus instead of simply receiving instructions.

At the heart of the hardware is a circuit board containing microprocessors. This replaces the wiring connecting traditional valves in a valve island to the bus, and will lead to thousands of pounds of savings for operators.

Through the use of "intelligent" valves courtesy of microprocessor control, prediction of impending valve failure is possible (Figure 1). This allows preventive maintenance to be carried out in scheduled downtime, eliminating expensive, unscheduled delays.

Figure 1 The diagnostic capability of Norgren's Fieldbus II

This diagnostic capability allows maintenance to be carried out quickly and efficiently, saving engineers the task of identifying the problem and locating the failed valve.

Richard Pell, valves product manager, says this is a major step forward in pneumatic automation control.

"Each valve on the valve island connects into the circuit board, like plugging in an electrical appliance - there is no tricky wiring to contend with. The system can interrogate valves individually, allowing information about response time and the number of cycles completed by each valve to be fed back to the work station.

"In principle it is similar to a heart monitor in an intensive care unit - each time the valve opens or closes it is recorded. You can tell as soon as a valve stops functioning at its optimum level because its response time slows down. This leaves you ample time to replace it during scheduled maintenance before it fails", he said.

Data collected from the valve also make the valve manufacturer accountable, for the first time, for the life of the valve.

Pell said: "The technology enables us to make guarantees about the valves we sell. It's like a milometer for valves; if a Norgren valve fails before it has performed the number of cycles we guarantee, we will replace it free of charge."

Fieldbus II is designed so that, for the first time, any one of four fieldbus protocols can be used without the need for rewiring or changes to the hardware installation. A fieldbus "node" converts the system to the chosen protocol.

Each protocol is plugged in and lifted out of the system without the need for complicated rewiring, taking the headache out of choosing the right protocol. Fieldbus II is compatible with Profibus DP, Device Net, CANopen, Interbus-S and can be linked to an As-interface.

The chosen protocol will be translated on to the circuit board of all connected valve islands, enabling 64 valves around a plant to be driven by only one fieldbus driver,

The introduction of V20/V22 solenoid valves, with two 3/2 valves on one valve island "slice" means each valve island can be half the size and half the cost of a traditional one.

"In the past, a 3/2 valve would have taken up one station of the valve island. Now we are able to 'double up' the 3/2 functions per 'valve slice', therefore halving the size and price of a traditional valve island", said Pell.

Fieldbus II adds to Norgren's complement of "intelligent" products. Intelligent FRL units, which tell operators when preventive maintenance is required, were shown at Manufacturing Week last year.

Looking to the future, remote diagnostic capability will allow engineers maintaining fieldbus systems in inaccessible locations to do their job in a fraction of the time currently required, again significantly reducing associated maintenance and manpower costs.

Ultimately, the development of intelligent actuators will be the final stage in ensuring that each element of the pneumatic process runs to optimum efficiency at all times, led by two-way communication between pneumatic components and their operators.

For further information, please contact: Peter Heath, Countrywide Porter Novelli. Tel: +44 (0) 1295 224400; Fax: +44 (0) 1295 224444; or Richard Lawson, Norgren. Tel: +44 (0) 1543 413444; Fax; + 44 (0) 1543 411449.