RS425 Contactless Torque Transducer


The Datum Electronics Series RS425 contactless torque transducer has been designed to fit easily in line with any drive-train or test rig, using either a spline or key-way shaft. This type of torque sensor has many advantages over other torque measurement systems, including zero bearing friction, high speed and high torque applications.

The Series 425 Contactless Torque Transducers can be adapted to replace existing drive shafts on test rigs and in drive lines, saving the time and cost of designing in special couplings and intermediate shafts to accommodate conventional torque transducers. We are able to modify the ends of the transducer to best suit your requirements, and can even design bespoke ends to fit. By measuring torque on longer drive shaft, you prove the accuracy of the measurement and its tolerance to offset loads. Using a direct replacement with a lightweight rotor the dynamics of the driveline are maintained.

The RS425 rotary bearingless torque transducer utilises a strain gauged shaft for accurate and reliable torque measurement and a set of rotating on shaft conditioning electronics, where 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 and rotary torque measurement to be made. Not only does the RS425 Series offer great technical advantages, but this range of contactless torque sensors are also competitively priced.

The RS425 Contactless Torque Sensor Range

The RS425 series contactless torque transducer is not limited by bearings; therefore it can be used at higher speeds and places with no bearing 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,  bespoke torque transducers (where the same modular elements have been applied)  are also available, from 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.

The Competitive Edge

The Series RS425 contactless torque transducer 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 a 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.

Torque Sensor Instrumentation

The Series RS425 contactless torque transducer is compatible with our Datum Universal Interface (DUI), 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.

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

A popular option is to view data from the transducer on a PC or laptop for torque data analysis. Our DUI software has been developed to allow the user 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 torque transducer data can be displayed and logged at the touch of a button with  DUI.

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 SENSORS Size 1 Size 2 Size 3 Size 4
TORQUE RANGE 0-100Nm 0-500Nm 0-2,000Nm 0-10,000Nm
Keyway or Spline Shaft
Various SCADA Outputs, including 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


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