Non Contact Rotary Torque Transducers Type RS425

Bearing-less Torque Sensor with completely separate rotor and stator.

1000Nm Torque SensorThe Datum Electronics Series RS425 non-contact rotary torque transducers have been designed to fit easily in line with any drivetrain or test bed using either a spline or keyway shaft. We are able to modify the ends of the transducer to best suit your requirements, and can even design bespoke ends to fit. This type of transducer has many advantages over other torque systems including: zero bearing friction, high speed and high torque applications. 

The RS425 torque transducer utilises a strain gauged shaft for accurate and reliable torque measurement and a set of rotating on shaft conditioning electronics, the digital signals are transmitted to the non-rotating part of the system or stator providing a reliable and highly accurate torque measurement solution. The rotor is continuously powered enabling static torque measurement to be made. Not only does the RS425 Series offer great technical advantages but the range of torque sensors are competitively priced.Torque Sensor Range and Torque Transducers

The RS425 Torque Sensor Range

The RS425 series torque transducer is not limited by bearings; therefore it can be used at higher speeds, and places no bearings loads on to the shaft. The stator needs to be mounted in relation to the shaft within an operating envelope of +/- 3 to 5mm. The standard range can measure torque ranges from 0Nm up to 10kNm, the same modular elements have been applied to bespoke torque transducers for use down as low as 1Nm and up to 500kNm. 

Using our new generation of electronics as found in our industry standard M425 Torque transducer, the RS425 gives customers the ability to choose the sample rate that they need from 1 up to 4000sps, with higher resolution using up to 24bit technology.

RS425 Rotary Torque Sensor Specifications

RS425 SERIES Size 1 Size 2 Size 3 Size 4
TORQUE RANGE 0-100Nm 0-500Nm 0-2,000Nm 0-10,000Nm
Keyway or Spline Shaft



RS485 as standard
DIGITAL: USB, Ethernet, RS485/232 and USB memory logging
ANALOGUE: 3 Channels of Torque, Speed and Power as 0-10V/4-20mA
Strain gauge signal, digital on-shaft
with inductive loop
22,000rpm 20,000rpm 16,000rpm 10,000rpm
OUTPUT DATA 1-4000sps

In many cases higher RPM ratings can be attained - please call our engineering team to discuss you applications

The Competitive Edge

The Series RS425 transmits calibrated digital data as this is a cleaner and more defined method of transmitting data. The on-shaft signal from the strain gauge is converted to a digital signal and amplified on shaft. It is this signal that is taken off the shaft and processed by either with our DUI; Datum Universal Interface, or with our free of charge GUI software, providing the end user with clean and definitive data transmission.


The Series RS425 transducer is compatible with our new DUI; Datum Universal interface which gives a range of digital and analogue outputs as well as a digital display of the torque speed and power. It can also be set in a legacy mode to work with our older range of indicators and displays

A popular option is to view data from the transducer on a PC or laptop for torque data analysis. Our GUI software has been developed to allow the user to view the torque data in real time with optional data analysis for performance monitoring and control. Using a simple USB interface, or Ethernet connection the transducer data can be displayed and logged at the touch of a button with our GUI. 

Analogue Options 


If an analogue signal is required, our Series 425 torque transducers are able to provide either 4-20mA or 0-10VDC output with our DUI; by converting the digital data signal from the torque transducer to an analogue signal. However, the effect of external or electrical noise can impact upon signal strength and definition in this instance. Other commercial applications may use slip rings or analogue signals to transmit data, but the Datum Electronics series 425 outputs digital as standard. 

If your requirements dictate anything above our standard torque sensor range of 10,000Nm we can and have engineered torque measurement transducers up to 500,000Nm. 

RS425 Torque Range
  • Lightweight Torque transducer with completely separate rotor and
    stator set
  • No mechanical friction, long-term operation reduced maintenance
  • Ideal keyway shaft for easy fitting to test rigs and drive systems
  • Spline shafts are also available as an alternative to a keyway shaft
  • No bearings – ideal for high speed applications
  • Standard RS425 torque transducer range available from 0Nm-10,000Nm
  • Analogue Output available & compatible with LABVIEW software
  • Ideal for fully sealed or underwater applications (IP 68) system upgrade
  • Accurate On Shaft Torque Measurement
  • Flexible shaft fittings (Spline or keyway shaft)
  • Modular System Assembly
  • Non-contact Signal Transmission
  • Proven Technology
  • Low Maintenance
  • Simple Linear Calibration
  • Engineered to fit most drive components
  • Rotary and Static Torque Measurement
  • Optional Analogue Data Output
  • LABVIEW compatible


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