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SP2800 data sheet - .PDF file.

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LWG data sheet - .PDF file.

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EPT3100 data sheet - .PDF file.

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EPTT5100 data sheet - .PDF file.

Garford Farm Machinery is utilising the SP2800 series rotary potentiometer, LWG linear position sensor, EPT3100 pressure sensor and EPTT5100 combined pressure and temperature sensor from Variohm Eurosensor in its Robocrop Inrow Weeder.

The Robocrop Inrow Weeder uses a video image analysis technique to locate crop plants through pixel and colour recognition and then use this information to control individual rotating weeding discs that actually hoe the area between the plants (inter-row) or in line with the plants (inter-plant), eradicating competing weeds but leaving crops intact.

The Inrow Weeder features multiple individual discs that operate across several crop rows with a maximum width of 6m. The rotation of each disc is synchronised with the forward speed of the tractor and the plant positional information from an imaging camera that can cover a 2m width. Each weeding disc is coupled to a hydraulic motor, driven via a proportional valve controlled by the cab-mounted Robocrop computer, which includes an HMI display to select modes and display operational information.

To achieve accurate lateral guidance of the equipment, a Variohm SP2800 series rotary potentiometer is located on the ground-contacting steering discs and feeds back steering angle information to the system. Garford uses the Variohm LWG series linear potentiometer on the side-shift to feed back lateral position information to the inter-row hydraulic servo system. It also provides a steering aid for the driver when the machine is set up as an in-row weeder.

Click on the links above to download the relevant data sheets.

Key benefits of product application


  • The 28mm-diameter SP2800 series angle sensor features conductive plastic technology with multiple-layer tracks in combination with precious-metal, multi-fingered wipers arranged in a preloaded design that ensures high resistance to shock and vibration.
  • For Garford, the sensor is supplied in an IP67 sealed temperature-resistant Duraplast plastic housing; aluminium-housed alternatives are available.
  • With a repeatability of 0.01 per cent of measuring range and an operating temperature range of -40°C to +150°C, the SP2800 ensures a long working life of more than 50 million cycles with excellent reliability, competitive costs and straightforward installation.


  • The LWG linear position sensor from Novotechnik achieves a high-resolution potentiometric output achieved with a conductive plastic resistance element and a precious-metal, multi-finger wiper system with elastomer damping mounted directly on the actuating rod — which is supported with twin bearings for maximum durability.
  • With a shock rating of 50g and vibration to 9g at 2,000Hz, the robust LWG linear position sensor provides a resolution of better than 0.01mm over a temperature range from -30ºC to +100ºC — with an operational life of more than 50 million movements.
  • For this application, the IP65-rated unit is actually mounted on the outside of the side-shift assembly on backlash-free pivot heads, with the anodised aluminium housing and stainless steel actuating rod fully exposed to the elements.
  • Electrical connection is through M12, IP67-rated sealed connectors. Across the LWG series, electrical stroke ranges from 50mm to 750mm are available.

EPT3100 and EPTT5100

  • Variohm’s EPT3100 pressure and EPTT5100 combined pressure and temperature sensors are used to monitor the input and output hydraulic pressures and return temperature information from the machine.
  • These pressure sensors feature high-level ASIC output circuitry with a thin-film strain-gauge pressure measuring cell covering a range of pressures.
  • For the combined versions, temperature measurement in gas or liquid is via a PT1000-compatible sensor with a rated range of -50°C to +150°C.
  • With IP66 or IP67 sealing and a high-strength stainless steel finish, they feature industry-standard port interfaces with sleeved electrical cable and optional boot protection.
  • Through both ranges, a choice of voltage and current output options is available.

Variohm Eurosensor

Founded in 1974, Variohm Eurosensor has been the leading single source supplier of sensors and associated electronic systems for over 40 years.
Variohm’s product portfolio includes sensors and transducers for; position, pressure, temperature and load. With a technical sales support team ready for new challenges, Variohm can ensure that the most suitable sensor will be selected for applications in any industry.

Based in Towcester, Northamptonshire, Variohm Eurosensor has been the leading single source supplier of industrial sensors and associated electronic systems since 1974.

With a technical sales support team, receiving regular product training, Variohm has the structure and financial strength to deliver technical support and quality service along with expert up-to-date advice on their entire product portfolio. Variohm’s ability to design, develop, source and deliver a vast range of sensor solutions means that the sales support team is able to work with customers throughout their entire project, enabling customers to influence how their products work.

Variohm’s aim is to provide an efficient, cost effective, flexible service to customers, irrespective of their size, business or geographical location.

Variohm Eurosensor are part of the Variohm Holdings Group. Variohm Holdings as an entity can provide products to suit any sensing application in any industry and is eager to use it’s combined knowledge and skills to solve new applications.

Variohm Eurosensor – Sensors and transducers manufacturer, distributor and supply chain partner
Herga Technology – Switching and Sensing Solutions
Ixthus Instrumentation – Test and Measurement Division
Heason Technology – Motion Control Solutions

Variohm Eurosensor’s range of products monitor: –Position, Load, Pressure and Temperature

Position sensors include rotary and linear sensors, cable extension transducers and inclination sensors. Available in various contacting and non-contacting technologies, including Hall effect, incremental and absolute encoders and laser measurement.

Load and force sensing; load cells from 1g to 1000t capacities, available in a wide range of mechanical sizes and designs to suit all applications. High speed bagging controllers, torque transducers to measure both dynamic and static loads, with various mounting and electrical connection options.

Pressure transducers and switches to measure absolute, differential and gauge pressure up to 5000 Bar. These sensors are available is a wide range of outputs and also standard and customised housing options, with IP ratings up to IP69K.

Thermistors and probes offering a wide temperature measurement range, with excellent interchangeability and stability which are also space and flight approved or medically approved where appropriate. Custom and bespoke solutions are available and many are manufactured or modified on site.

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