Accurate Weight on the Fly
An estimated one out of three people is afraid to fly. Their constant thoughts of what might go wrong can be overwhelming. After all, when soaring 30,000 feet in the air, one cannot pull over for a pit stop in the rare case of an emergency. Fortunately, innovations in the industry are helping to improve systems and equipment—and thus easing the fears of the bug-eyed flier.
Before assembly of an aircraft can even begin, one of a plane’s most essential elements—the wings—must undergo strenuous force testing. Sophisticated system diagnostics are integrated, and rigorous maintenance schedules must be followed.
One Quebec wing manufacturer has been performing these tests for over 25 years. Because of the wide range of plane sizes, wing specifications are diverse and so are their test requirements. A Cessna wing’s force threshold is obviously less than a passenger jet’s threshold. Sturdy wings can be guaranteed by using a programmable indicator to interpret these force tests into a weight value. However, when Balances Industrielles Montréal (BIM) started working with the wing manufacturer in 2006, they observed that inefficient data capturing and collection were elements that could be corrected and streamlined with Rice Lake’s durable load cells and 920i® programmable indicator.
Simon says “plug in your load cell.” With Simon Grenier’s one-of-a-kind system, any load cell can be connected and display an accurate weight on the fly. Referencing a database of predetermined correction factors paired with load cell IDs, the system applies the appropriate factor before displaying the weight value.
Simon Grenier, programmer analyst for BIM, had an idea. Simon thought it would be ideal to use a variety of load cells for different wings tests to accommodate the different load requirements. With only two weight indicators on site, it would require the creation of a custom plug-and-play load cell system.
Simon contemplated the possibility of starting with a six-wire cable, but using only the standard four-wire connection and repurposing the additional two wires. Could he disguise an analog load cell as a digital load cell that could be recognized by the controller?
Simon began work on the plug-and-play load cell system. He applied resistance to the two supplementary wires—which are only on the connector and are not going to the load cell. “When we connect, it is linking the analog input that is sending a signal to it,” Simon explains. “The signal travels through the resistance and returns with a value we use to assign an ID for that load cell. Because each load cell undergoes a 25,000-pound bench test for calibration and we use the same simulator for each load cell in the system, we are able to calculate an accurate resistance factor for each load cell.
“In the database, we have a correction factor to the calibration that we have done with the simulator. So when we perform the 25,000-pound bench test, we determine the difference between what it’s supposed to show, with what we get. The multiplier required to bring it back to the correct value is added to the 920i database. If a portable bench test for 25,000 pounds would be easy to bring to the customer, we could have used something much simpler, but they are sending the load cell here without an indicator.”