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Product category: Loadcells, Force Sensors and Torque Sensors
News Release from: Datum Electronics | Subject: Series 420 Marine Torsionmeter
Edited by the Engineeringtalk Editorial Team on 08 February 2006

Meter checks ship transmission
performance

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Torsionmeter provides tool to access and monitor the performance and efficiency of a ship's transmission system using non-contact torque measurement of shaft torque, speed and power.

The Series 420 Marine Torsionmeter provides an accurate tool to access and monitor the performance and efficiency of a ship's transmission system It provides non-contact torque measurement of shaft torque, speed and power

The system is based on shaft strain gauges, a digital shaft rotor amplifier and two low power inductive loops to transmit power onto the shaft and transmit the data from the shaft.

The data is transmitted from the shaft in a digital format that can be processed and scaled off-shaft.

The data transmitted contains the torque level, the shaft speed and diagnostics data such as the on shaft voltage.

The torsionmeter consists of two rotating shafts (one port shaft and one starboard shaft), each with a Series 420 marine torque transducer installation.

The transducer can accurately measure the on shaft torque, the speed of rotation of the shaft and the power that is going through the shaft.

This is applicable to the port and starboard shafts.

Strain in the shafts is measured with strain gauges bonded to the shaft.

The output of the strain gauges is amplified and digitised on-shaft and transmitted via a Manchester encoded current modulation of the inductive coupled coils.

The current modulation is decoded by the off-shaft microcontroller and transmitted as an RS485 9600baud serial data stream to the control unit.

The on-shaft optical speed sensor receives pulses from the off-shaft LEDs as the shaft rotates and the on-shaft microcontroller calculates rotational speed by measuring the time between pulses.

The shaft rotational speed is also transmitted along with the strain signal.

The control unit applies preset calibration values to the data received from the shafts and displays torque in kNm.

The control unit also calculates power from torque and speed data.

The control unit uses the presence or not of a speed signal to accumulate shaft running hours for each shaft and this is displayed on the control unit.

The control unit transmits torque, speed and power data via RS485 to the remote displays.

The remote displays receive RS485 data and display torque, speed and power.

The displays are dimmable via a panel mounted potentiometer and have test button that forces the remote display microcontroller to display 888 on all displays.

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