Sensors and Joysticks from Curtiss-Wright Specified for Multi-Function Trailer Upgrade

The versatile, multi-function trailer, which sells in the UK and around the world, has recently benefited from a major upgrade of its control system and now features highly sophisticated electronics developed by control specialist Tedd Engineering.

Explaining the significance of the new control system Paul Bowles of Big Bale Company South says the control system is predominantly responsible for controlling and managing the Transtacker’s hydraulics. “The hydraulics perform the three principle functions of the Transtacker trailer, which are to pick up, lift and rotate bales from ground level to the machine’s trailer. This involves controlling the operation of large double tines and a turntable, which travel between zero and 180 degrees.”

He goes onto say that in the company’s experience, agricultural equipment is plagued with poor sensors so they were determined that sensors for the new control system would be tailored to do exactly what they wanted and would future-proof the functionality.

Big Bale South’s previous Transtacker model used pairs of proximity sensors to indicate the position of zero and 180 degrees, but as bales can vary in size their travel couldn’t be monitored accurately if they were larger or smaller than the specified size. This variance in bale size could cause the machine to freeze and reliability therefore became an issue.

“What we needed was a programmable sensor capable of providing a safe area within the function that would allow the machine to continue, and this is what the Penny + Giles (a legacy brand of Curtiss-Wright) sensors give us.” says Paul. “The contactless Hall effect SRH501P rotary position sensors enable us to increase or decrease the functional sensitivity and introduce error codes that, when detected, allow the machine to continue within safe limits.”

A list of systems options was presented by controls specialist Tedd Engineering and reviewed by Big Bale South, whose engineering team is experienced in the many different rotary sensors available. Significantly, within ten minutes of the Curtiss-Wright's SRH501P rotary position sensor being fitted to and operating on the Transtacker, the team decided it was the one for the job!

“It solved every problem instantly.” says Paul. “Among the options presented to us were no-contact types called snail shells but when there are gaps between sensors, especially in agricultural applications where conditions are incredibly harsh, they often get mud and crops on them and stop working. We now always specify that any sensors used must have a direct mechanical link with the function.”

Once the length of the arm and other details of the specification were calculated and they had the degrees of travel needed, the sensor was factory-programme.

“We needed a system that would tell us where every function was at all times. What we now have, compared to the previous proximity sensors, is fantastic. In effect, the rotary position sensor has given us fully-programmable functionality.”

The SRH501P rotary position sensors are used on three functions. The first is the zero to 180 degrees pick-up function, which lifts the bale from the ground and places it onto the machine. The second function controls the turntable, which can perform a straight vertical lift at 90 degrees. Alternatively, it can perform the third function, which is to lift and rotate through 90 degrees.

As well as rotary position sensors, Curtiss-Wright's JC6000 multi-axis joystick controllers were also specified for the Transtacker. These are currently programmed with only four of the six available axes because Big Bale’s engineers opted to future-proof the system with expandable operating capacity. The JC6000 joystick controller is coupled to a display unit in the tractor cab, which acts as a virtual terminal for the trailer’s ‘black box’ containing the machine’s software.

The control system is designed to make life as easy as possible for operators and enables them to simply push the joystick forward to begin the trailer’s operation. For the first function, the Transtacker lifts the bale onto the turntable, releases it and returns to position ready to pick up the next bale. The tractor doesn’t even need to stop to collect bales. The next function is initiated by pulling the joystick back, which lifts the turntable, rotates the bale and places it onto the back of the trailer. If bales need to be lifted without rotating them, the operator simply actuates one of the joysticks buttons while pulling the joystick back.

The display unit shows four joystick functions at all times and has five menu buttons. Pressing and holding any of the menu buttons changes the screen to show four different functions, which increases the functionality of the buttons on the JC6000 from four to a total of sixteen.

Commenting for Tedd Engineering, Richard Hooper says: “We specified JC6000 joysticks because we know they are well made, well engineered units and provide CAN (J1939) output. The SRH501P rotary position sensors were also very easy to integrate and the range of options is good so we knew we could immediately obtain the electrical output required to work with our existing circuit board.”

He adds that the old proximity sensors didn’t provide enough information across the full travel on the machine’s functionality because they were set a few degrees off the full travel of the system. This meant the system had only a few degrees within which to decelerate. By contrast, an angular sensor like the SRH501P knows where it is at all times and can control deceleration accurately.

Paul Bowles comments that, equally important for an agricultural application and especially for the Transtacker engineering team, was the mechanical robustness and generally rugged design of the sensors and joystick controllers.

Designed to provide an easy, simple and efficient way of collecting and stacking bales in the field, the Big Bale Transtacker takes full advantage of the functionality available with the control system to make the operator’s job easier and ensure safer operation. Examples include enabling the Transtacker’s new and improved pick-up function to be adjusted without the operator leaving the cab and ensuring that, for safety, the machine’s guide bar is automatically retracted when ‘Road Mode’ is selected. In addition, when the auto pick-up function on the JC6000 is activated, large double tines penetrate the bales holding them securely on the pick-up frame and lifting them clear of the ground without stopping or slowing the Transtacker’s forward movement.

Paul Bowles reports that to date, twenty-two machines have been delivered with the new control system and there are no reported problems despite the rugged operating environment.

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