Product category:
Pressure sensors
News Release from: Sensor-Technik UK | Subject: Standen Engineering
Edited by the Engineeringtalk Editorial
Team on 14 February 2002
CANbus proves a hot potato in the field
A CANbus-based system has helped Standen Engineering achieve savings in production costs while providing a higher control specification for its latest potato harvester.
As agricultural machines have developed in complexity and sophistication, customers have demanded more operator control The latest version of the Standen Engineering Vision potato harvester features 55 individual switching signals, with which the operator can control 30 individual functions
Standen Engineering has been manufacturing agricultural machinery in Ely, Cambridgeshire since the 1930s.
During the 1970s, as hydraulic controls became more common on farm machinery, the company was one of the first to use solenoid operated valves, switched from the tractor cab to operate the services on the machines.
In 1999, Standen's engineering team realised that the practical limits of wiring had been reached, especially as the wiring from the tractor to the harvester is 15m long and has to be able to be disconnected, often on a daily basis.
A 26-page control protocol was circulated to various electronics and hydraulics supply companies to obtain a practical solution.
Standen's main hydraulic valve supplier Bucher Hydraulic proposed a CANbus system using the robust and already proven Sensor-Technik Wiedemann modules with software written by Bucher's electronics division.
A prototype system was tested during the 2000 harvesting season, with four machines working during the 2001 season.
The systems have worked with the minimum of fine-tuning to the software, and have proved to be extremely reliable, giving Standen enough confidence for the 2002 production to build all machines with CANbus control system as standard.
The driver interface control unit has a membrane fascia, interfaced to the bus with a 56-channel input and 32 LED indicator output module.
To allow the operator to view and set defaults for flow rates, delay and response times and to monitor pressures in circuits, a Wachendorff OPUS Light four-line operator display panel is inset in the fascia.
Password-protected second and third levels of access to the display allow override parameters to be set by service engineers and a step-through operator diagnostic menu to be used in conjunction with the control panel to display valve coil current and voltage.
The system drives between 18 and 24 valves, depending on the customer specification for the machine.
During the development of the system several functions, which could only be manually preset on the harvester, have been able to be changed to in cab adjustments allowing the operator far more control on the quality of the crop sample produced by the harvester.
Optional automatic sensors for machine levelling, discharge elevator height, depth control and axle steering position can be plugged into the main ESX job processor.
Either an ESX- DIOS or ESX-DIOM slave module is used to achieve the required number of proportional or digital outputs.
Standen has been able to introduce the CANbus system and has achieved savings in production costs with a higher control specification.
This is mainly due to the savings in commissioning times, when the machine is first run up and the ease of in-field setting when the customer starts to operate the machine.
Because of the simplicity of the wiring loom required, bringing the wiring in house has made additional cost savings.
Specialist contractors produce only the distribution circuit board, which Standen has produced to interconnect the elements of the system and the fascia.
Development does not stand still and the ease of programming available allows for ongoing software upgrades to be flashed onto the processor module from a laptop computer in the field, giving the customer the benefits of improvements.
STW modules are single plug connection and in the unlikely event of a failure, a preprogrammed replacement can be fitted by a semiskilled person very quickly to keep the machine operating in what is a 24-7 programme to harvest the crop before the first frosts. Request a free brochure from Sensor-Technik UK ...
• Sensor-Technik UK: contact details and other news
• Email this article to a colleague
• Register for the free Engineeringtalk email newsletter
• Engineeringtalk Home Page
Search the Pro-Talk network of sites
