RMD Pro – the fully digital UV radiometer

The calibration uncertainty stated above is the expanded uncertainty of the calibration (k = 2, confidence level approx. 95 %) and applies to the calibration source and the calibration conditions. In use the measurement uncertainty is larger: spectral mismatch at the source actually used, the sensor temperature, ageing since calibration as well as distance and alignment to the source are added to it. How these combine into an uncertainty budget is explained under Measurement uncertainty in UV measurement.

Both devices measure irradiance and dose with the same sensors. The difference lies in the recording and in the connection to the PC.

Both instruments measure with the same digital sensors on two inputs and display irradiance, illuminance and dose. The RMD Pro adds the internal memory of 8 GB, on which measurement series with an adjustable interval of 1 s to 15 min are stored as a CSV file and read via USB. Anyone who only wants to read momentary values or the dose on the instrument is served by the RMD; for records and long-term measurements the RMD Pro is intended.

The digital sensors work with 24-bit conversion and a dynamic range of 10⁷:1; the resolution is 0.001 µW/cm², the measuring range extends to 1 or 10 W/cm² depending on the spectral range. One and the same UVC sensor thus measures stray radiation at the workplace of a few µW/cm² and the irradiance directly at the reactor window without switching ranges. The typical calibration uncertainty is 4.5–6.0 % (k = 2).

In addition to the spectral ranges UVC, UVB, UVA, UVA+, UVBB, VISB and LUX there are sensors with biological weighting: erythema plus UVA for tanning beds and phototherapy as well as NDT with 365 nm plus LUX for fluorescent penetrant testing. For the risk assessment per DIN EN 62471:2009-03 and DIN EN 14255-1:2005 the actinic effect is measured with the matching weighted sensor; the sensor table of the product page lists the ranges with their measuring ranges.

The calibration certificate states the expanded calibration uncertainty with k = 2; for the RMD and the RMD Pro it is typically 4.5–6.0 %. In use the measurement uncertainty is larger, because spectral mismatch at the source actually used, sensor temperature, ageing and measuring geometry are added to it. How these combine into an uncertainty budget is explained under Measurement uncertainty in UV measurement.

Yes, the calibration data is stored directly in the radiometer sensors, which makes it easy to retrofit them at any time. By using different sensors with one UV radiometer RMD, you can react flexibly to different measurement requirements.

Yes, the radiometer can determine the dose automatically. The RMD Pro also saves it. The unit of dose is J/m². This corresponds to one watt times one second and is related to an area, e.g. one square meter. So J/m² is also Ws/m².

Yes, the RMD is suitable for process control. The sensors have a very high dynamic range for this purpose. Measure with the RMD UV radiometer at the point on the surface that you illuminate with UV. Carry out these measurements weekly, for example. For continuous measurements, we recommend our PLC and inline sensors. These are mounted at a lateral position and can also monitor the UV system during production. The adjustment is then carried out using the weekly measurements, for example.

The RMD UV radiometer is suitable for measuring PWM (pulse width modulation) dimmed LEDs. Due to the internal averaging and the sampling rate of the 24 bit ADC, the time average of the irradiance is output precisely. For the same reason, however, individual pulses or flashes cannot be measured.

For measuring fast UV systems, we recommend our curelog fast-measuring belt radiometers, which measure very quickly with up to 2000 measurements per second. For measurements of pulsed flash lamps, we recommend our integrating spectroradiometers UVpad and UVpad E. These also output the time-averaged irradiance as well as the dose.

Yes, the RMD UV radiometer is suitable for UV risk assessment in the workplace. It enables precise measurements of UV radiation at very low irradiance levels. This means that the daily exposure dose of 30 J/m² can be measured.

For general measurements for UV risk assessment at the workplace, we recommend our erythema sensor. Assessments, e.g. for LEDs, can also be carried out with the UVA+ sensor and a simplified weighting with the erythema function S(λ). 

No. For permanent outdoor use, Opsytec Dr. Gröbel offers the RM-12 and IP-65 sensors. The RM-12 is IP-65 waterproof, the RMD is not. The RMD should therefore only be used in dry environments.

The RMD Pro from Opsytec Dr. Gröbel records the data and is suitable for permanent monitoring. Please also compare our RMD Touch Laboratory UV radiometer or the cheaper SPS sensors.

Yes, Opsytec Dr. Gröbel recommends the DVGW reference radiometer RMD Pro with DVGW sensors for DVGW/ÖNORM-compliant measurements. The UV reference radiometer meets the required standards. The DVGW sensors can be calibrated in accordance with DIN 19294-3 for low-pressure lamps or DIN 19294-4 for medium-pressure lamps. We also have a large selection of available UV LEDs in stock as calibration lamps for special calibration requirements, such as UV LEDs.

Yes, the measurement data is saved directly as a CSV file on the 8 GB memory. You can open it in Excel. The CSV file contains the date & time, measuring device and sensor identification, the irradiance, the dose and the sensor temperature.

UV low-pressure lamps and UVC amalgam lamps usually reach irradiances below 200 mW/cm². UV spot light sources such as the HP-120i, by contrast, lie in the range of a few W/cm².

UV LEDs emit at 365, 385, 395 or 405 nm, for example. The UVA+ sensor was developed for measuring them - it covers 330 to 455 nm and thus captures the common LED wavelengths with one sensitivity curve.

For medical applications, process reliability and calibration come first. Our sensors are stable over the long term and can be recalibrated; repair and spare-parts service are available for many years. Applications with different UV emitters can be measured reproducibly with our radiometer sensors. Where all spectral ranges are to be captured at once, the UVpad is the right choice.

For risk assessments and considerations of occupational safety, DIN EN 14255-1:2005 governs the measurement and assessment of personal exposure to artificial optical radiation. The standard itself contains no limit values - these are given in directive 2006/25/EC on artificial optical radiation, which has been transposed into national law. For UVA radiation the limit there is 10⁴ J/m².

For such measurements the sensors have to be sensitive enough. Choose a sensor - UVA or UVB, for example - with the measuring range 0 to 2 mW/cm².

For process monitoring, the spectral range of the sensor follows the UV application and therefore usually the photoinitiator. The measuring ranges stated are our recommendations; they can be adapted to customer requirements. Please ask us about this or state the required measuring range with your order.

Scope of delivery: the radiometer, the power supply unit, a USB cable, the manual and one sensor to suit the application; with the RMD Pro additionally an SD card and the PC software. Calibration is traceable to PTB standards, with a factory calibration certificate and optionally with an ISO 17025 calibration certificate.

The smaller version without internal memory, recording, real-time clock, USB port and PC software. The RMD can be upgraded to an RMD Pro later with the upgrade kit (order number 814403); the device does not have to be sent in for that.

Two sensors can be operated on one RMD at the same time. The sensors are calibrated with traceability to the PTB and can be recalibrated.

All designs can be connected to the RMD and the RMD Pro. For some applications - where only a low overall height is available or at high temperatures - we recommend one of the other sensor series.

Accredited ISO 17025 calibration and testing in our own calibration laboratory. On delivery the device is already factory-calibrated.

The RMD is used for dose measurement in irradiation experiments and for UVC decontamination. Most recently published:

• From minutes to bounds: A probabilistic UV-C control and a shape-only morphological fingerprint for postharvest Colletotrichum inactivation in cacao and coffee processing – Ahn, E.; Baek, I.; Lim, S. et al. · Food Control · 2026
• Hybrid epoxy-LMPAEK composite co-cured joints: A study on UVO pretreatment and its effect on interlaminar toughness — Katz, L.; Bor, T.; Helthuis, N. et al. · Composites Part B: Engineering · 2026
• Trainable soft electronics with memory in liquid crystal polymers — Lyu, P.; Weima, S. A. M.; Baek, J. et al. · Science Advances · 2026
• UV-C Irradiation Effectiveness on Mpox-Virus-Contaminated Surfaces — Gidari, A.; Sabbatini, S.; Pallotto, C. et al. · Pathogens · 2026
• Differential responses of Cacao pathogens Colletotrichum gloeosporioides and Pestalotiopsis sp. to UVB 305 nm and UVC 275 nm – Baek, I.; Jang, J. H.; Lim, S. et al. · Scientific Reports · 2025

The details come from Crossref. Authorship and content rest with the respective research groups.

These are the rules most often consulted in practice for radiometers and sensors — from measurement through limits to the requirements on the device:

• DIN EN ISO/IEC 17025:2018-03 — General requirements for the competence of testing and calibration laboratories
• DIN EN 62471:2009-03 — Photobiological safety of lamps and lamp systems
• DIN EN 14255-1:2005 — Measurement and assessment of personal exposure to incoherent optical radiation — Part 1: UV radiation from artificial sources in the workplace

All rules for radiometers and sensors are listed in the standards finder.

Not a normative reference. What counts is always the currently valid edition in the original text.