Four times four – HBM digital load cells for weighbridges

Westco Ltd., situated in southwest England, is a very successful scale business. The quality of the weighbridges produced by Westco, as well as the scale maintenance and calibration service it provides, enjoy a very high reputation throughout the country.

That is why Princess Yachts, a manufacturer of luxury yachts based in Plymouth, asked Westco to supply a system for weighing boats while suspended in slings from a large four-legged portal crane. The design uses four small weighbridge decks, each fitted with four load cells – one for each wheel of the crane – so that a total of 16 load cells send measurement data to a display unit.

The challenge …

This application faced three different problems. First, there was corner-load balancing. Second, the four platforms had to be adjusted among themselves. Finally, a defective load cell had to be detected with ease from among 16 load cells, each with a nominal load of 40 t.

… the HBM solution

The answer was C16i digital load cells and the TRADE software package from HBM. The system enables 16 load cells to be operated over a shared COM port on a PC. The PC does not have to be located at the measuring site where it is subjected to environmental effects. Rather, it can be off-site, perhaps in an office.

<l>“In comparison with an analog system this was child’s play to use. The cabling was easy and the whole installation and setup procedure was much better. It worked out really well!” (Mark Bazeley, installation engineer)</l>

The benefits of digital weighing systems

Company Director Colin Hayman says that the decision to go for this system was taken because it “enables diagnostics to get right down to the level of an individual load cell”. Moreover, for the purpose of monitoring balance it proved possible to display different scale setups, such as the sum of both the front two pads, or the sum of both the rear pads. It was only during installation that they first realized how much easier it was to use compared to an analog system. The main reason for this was the TRADE software, which performs cornerload balancing and calibration at the touch of a button.

In normal operation the user has four display windows open, one for each pad, so that he can monitor the balance(which is very important for a yacht), plus one additional window for the total weight.

Success with a positive outcome

Since being commissioned in July 2002 the scale has worked well. In fact, Westco has been asked to supply additional equipment. Both Westco and Princess Yachts are delighted.

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 Four times four - HBM digital load cells for weighbridges (299 kB)