Loop powered sensors

Loop Powered Vibration Sensors - 4-20mA Transmitter


4-20mA output

In-built transmitter

Easily configurable with PLC/SCADA/DCS systems


No Additional Power Required

Easy Wiring


Our advance 4-20mA vibration transmitters or loop powered sensors, are engineered for use with the latest PLC (programmable logic controller), BMS (building management system), or SCADA (supervisory control and data acquisition) technologies, offering sophisticated solutions for condition monitoring and preventative maintenance.

The purpose of the 4-20 mA analog current loop is to transmit the signal from an analog vibration sensor over a distance in the form of a current signal. ROKADE's loop power sensors output a 4-20 mA current that is proportional to the overall vibration of the equipment or machinery they are monitoring. This output current has a range of 4-20 mA (4 mA normally representing the sensor's zero-level output, and 20 mA representing the sensor's full-scale output).

Only two wires are required to send the current signal and also supply power to the sensor. A loop supply voltage is used to power the remote sensor. The remote sensor regulates the loop current such that the loop current represents the value of the parameter being measured by the sensor. A series resistor RL at the loop power supply converts this current to a voltage that can be used by the process monitor/controller to record or distribute the parameter being measured.

product diagram

Loop powered sensors


No Additional Power Required

First and foremost, it might not be feasible to supply additional power to your system if your application is in a remote area, for example. In this case, your transmitter might be powered by a battery, solar cell, or some other power source and the other devices in the system would derive their power from the transmitter. The expense of running additional lines may also make additional power other than just the 4-20 mA signal cost prohibitive.

Easy Wiring

As there is only one power source for the entire system (often supplied by the transmitter which is outputting the 4-20 mA signal), loop-powered devices are also incredibly simple to setup. Only two wires, the positive (+) and negative (-) connections to the current loop, are required. This is in contrast to three and four wire setups, which incorporate an external power supply into the mix. This makes installation complexity minimal.





Pulp and Paper




Building services


Technical Specifications

Mounted Base Resonance 5kHz min
Velocity Ranges see: 'How To Order' table ±10%
Nominal 80Hz at 22oC
Frequency Response 10Hz (600cpm) to 1kHz (60kcpm) ± 5% - ISO10816
Isolation Base isolated
Range 50g peak
Transverse Sensitivity Less than 5%

Mechanical Specifications

Case Material Stainless Steel
Sensing Element/Construction PZT/Compression
Mounting Torque 8Nm
Weight 150gms (nominal)
Maximum Cable Length 1000 metres
Standard Cable Length 5 metres
Screened Cable Braided - length to be specified with order
Mounting Threads see: ‘How To Order ’ table

Electrical Specifications

Current Output 4-20mA DC proportional to Velocity Range
Supply Voltage 15-30 Volts DC (for 4-20mA)
Settling Time 2 seconds
Output Impedance Loop Resistance 600 Ohms max. at 24 Volts
Case Isolation >108 Ohms at 500 Volts

Environmental Specifications

Operating Temperature Range -25 to 90oC
Sealing IP65
Maximum Shock 5000g
EMC EN61326-1:2013

Typical Frequency Response

Typical Frequency Response









Air Handlers








Machine Tooling

Process Equipment

loop-powered-sensors application

Vibration sensor should be firmly fixed to a flat surface (spot face surface may be needed to be produced and cable anchored to sensor body.)

How To Order