An RF moisture meter for % water content in boards and foodstuff

RFM-1000 Series

measures total moisture
non-contact method
200 measurements per second

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A radio frequency moisture meter.

This measurement technique establishes a radio frequency fringe field around the sensor that penetrates into the product being measured. Water has a very high dielectric constant (about 20 times higher than solid material) and this can be used to accurately monitor the varying moisture content of plaster board, particle board, and plywood as they pass over the sensor. This system is also a popular method to monitor bean, grain and other web based products such as textiles, paper and cardboard.

The product being measured passes in close proximity to the sensor (about 6mm) and can, if necessary, be behind glass. There is a wide variety of sensors available:

  • 8", 10",24", and 48" open frame sensor for board, web, paper and cardboard products
  • 3.5" and 5" diameter circular sensors for other applications

The sensor is set to a resonant frequency, and as the water content of the product passing close to the sensor varies, the dielectric value, and therefore resonant frequency, changes. These frequency changes relate to the water content of the product and once calibrated are converted to display and output moisture content of the product.


Measurement principle

Penetrative radio frequency


Stand alone

Range and accuracy

0 to 1 %  ± 0.05 %

0 to 10 %  ± 0.1 %

10 to 30 %  ± 0.25 %

30 to 80 % ± 0.5 %

Operating frequency

3 to 7 MHz

Measurement speed

100, 200 or 400 measurements per second, user selectable

Operating temperature

0 to +5 °C (high temperature version up to 250 °C)

Antenna styles

8", 10", 24" and 48" open frame, 3.5" and 5" circular

Processor Specifications


Powder coat painted aluminium, optional stainless steel


NEMA 4 (IP 65)


Touch screen colour LCD, or two line VFD with limited keypad


90-240 VAC



CE marked


Materials open frame

Anodized aluminium with Teflon or ceramic spacers

Materials circular

3.5" Teflon and 316 SS, 5" ceramic and 316 SS


Power voltage

15 VDC or 90 to 260 VAC via remote power supply (supplied)



Dual isolated 4 to 20 mA, RS232, RS-485

Optional communications

Ethernet, Profibus, Decivenet, Modbus (RTU & TCP/IP, Profinet)


Product temperature sensor, product loss/presence photocells

All specifications subject to change