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RFM300-M Series

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Digital refractometer

With 3-decimal / 0-100 Brix (1.58 RI) scales, Peltier control and keypad. Perfect for measurement and control in demanding food, beverage, chemical and industrial applications.

RFM300-M Series refractometers are capable of measuring non-homogenous samples such as fruit juice with pulp, opaque chemical compounds and emulsions that are normally difficult to read with optical refractometers or those digital refractometers that do not address the need to measure “difficult samples.”

The instrument’s new case is ergonomically designed so that any spills are dealt with by the sloping shape of the case or by the PEEK spill barrier that surrounds the shallow, easy-clean stainless steel prism dish.

The large, clear buttons and 4” high resolution screen help facilitate operation in factory environments, and combined with our latest GUI, help the operator quickly manoeuvre through the menus. On-screen prompts support simple operation such as Method loading, calibration and routine maintenance guiding even the newest member of your staff.
RFID swipe technology comes as standard, providing clearance and a log of operator and configuration functions; especially useful when being used in FDA regulated environments operating in accordance with 21 CFR Part 11, or where good practice is adopted, e.g. as part of HACCP.


RFM330-M RFM340-M
Refractive Index
Sugar (°Brix)
1.32 – 1.58
1.32 – 1.58
Refractive Index
Sugar (°Brix)
0.0001 / 0.00001 (selectable)
0.1 / 0.01 (selectable)
0.000001 (selectable up to 6 d.p.)
0.01/0.001 (selectable up to 3 d.p.)
Refractive IndexSugar (°Brix)
±0.00005±0.04 ±0.00002 (1.32 – 1.38 RI)
±0.00004 (1.38 – 1.58 RI)±0.010     (0 – 30 °Brix)
±0.030     (30 – 100 °Brix)
Precision (Reproducibility)
Refractive Index
Sugar (°Brix)
± 0.00001
± 0.01
± 0.000005 (6 d.p.)
± 0.005 (3 d.p.)
User Scale Library 20+ pre-programmed scales including HFCS (3), sugar (4), sucrose SG (3), NaCl, Butyro, Wine Must (5), Urine SG (3), PHR-MEAN and more; plus customer programmable user scales via PC.
Reading Time Minimum 4 seconds (dependant on precision required)
Measuring Temperature Range 0°C or 10°C below ambient whichever is greater to 70°C
Temperature Sensor Accuracy ± 0.03 °C
Sample Temperature Stability ± 0.05 °C
Temperature Compensation
Sucrose (°Brix)
AG Fluids
5 – 80 °C
5 – 40 °C
Simple coefficient (units/ °C) or polynomial function
Temperature Stability Checks None/delay time/repeatability/ Smart (independently selectable by Method)
Sample Illumination Light Emitting Diode 589nm (100,000+ hours)
Prism / Dish Artificial Sapphire / Stainless Steel 316 / PEEK (spill barrier)
Prism Seal Silicon/Resin
Interfaces 3 x USB (A), 1 x USB (B), 1 x Ethernet, RS232 via USB adaptor (optional accessory)
Power Instrument: 24 V DC, ±5%, <2A
External PSU: 100-240V, 50-60Hz (supplied)
Humidity Range <90% RH (non-condensing)