PLATO MONITOR is a variant of SONATEC and allows measuring original gravity of beer in the manufacturing process. Typically, original gravity is determined during beer filtration and in front of the filler.


PLATO MONITOR is a special version of SONATEC and continuously measures the speed of sound through the product. The instrument is designed for applications requiring maximum sensitivity and highest accuracy. It is easy to operate and maintenance-free. For sound velocity measurement a sound pulse is created by a piezo-element in a sonic transmitter. It moves perpendicular to the product flow towards a sonic receiver where it is detected. Since the distance between transmitter and receiver is known, the sound velocity can easily be calculated by measuring the travel time of the sonic signal. As a specific property of each liquid, the correlation between concentration and sound velocity can be described by a mathematical polynomial. With decades of experience and our own laboratory facilities, Centec know the polynomials for a large number of products. Any temperature drifts of the measured signal are automatically compensated for by an internal Pt1000 sensor.

European patent application: 1 439 438 B1

  • Most accurate technology to determine original gravity in the manufacturing process
  • Patented compact design with local display available
  • Hygienic execution and full CIP capability
  • Easy to operate and maintenance-free

Technical Data

Measuring Range 0 - 25 °Plato
Accuracy ± 0,05 °Plato
Measuring Temperature Range -3 - +25 °C
Response Time ≤ 1 s
Pressure of Operation max. 16 bar
Temperature of Operation - 25 - + 125 °C
Temperature Sensor Pt1000
Material 1.4404/1.4435/AISI 316L; Hastelloy; Tantal; others on request
Connections Varivent© DN65; dairy fitting DIN11851 DN65; others on request
Input Transmitter Version 6 x digital (24 VDC)
Output Transmitter Version 3 x digital (24 VDC) & 2 x analog (4 - 20 mA)
Profibus DP Transmitter Versionoption
Profibus DP Sensor (w/o local display) standard
Enclosure Rating IP65
Power Supply 24 VDC


Tel.: +49 6181 18 78 0
Fax: +49 6181 18 78 50


PLATO MONITOR - Datasheet / Datenblatt
(0,77 MB, PDF, EN/DE)