Ethernet UV sensor PLC.net with PoE

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.

The PLC.net is powered via Power over Ethernet per IEEE 802.3af from the network switch; a separate power supply is not needed. A single network cable is therefore sufficient for power and data, which simplifies installation at hard-to-reach measuring points. If no PoE switch is available, a PoE injector between the switch and the sensor takes over the power supply.

The sensor updates the reading typically every 20 ms, at the latest every 100 ms, and provides it simultaneously via Modbus TCP on port 502 and via the HTTP interface. This rate is sufficient for controlling a UV system via the PLC; for time profiles of individual lamp pulses with millisecond resolution a data logger such as the curelog with up to 2000 Hz is intended.

PLC.net is supplied in the same seven spectral ranges as the other PLC sensors: UVC 200–280 nm, UVB 280–315 nm, UVA 315–400 nm, UVA+ 330–455 nm, UVBB 230–400 nm, VISB 400–480 nm and LUX with V(λ) weighting. The measuring range extends to 10,000 mW/cm² as standard; for low-pressure UVC lamps in disinfection systems a sensitive version up to 10,000 µW/cm² is intended.

Yes. The PLC.net provides its readings over Modbus TCP on standard port 502, in Float32 format and in mW/cm², with a resolution of 0.001 mW/cm². It can therefore be attached to a Modbus master in the controller without additional hardware. The same values are available in parallel from an HTTP interface as JSON; the integrated web server also exports them as a CSV file.

Through a network-capable interface. The PLC.net sits on the network over LAN and provides the irradiance over Modbus TCP as Float32 in mW/cm² and over HTTP as JSON; both routes can be polled by common SCADA and process control systems. Alongside the reading, device information, calibration data and status parameters can be read – only then can a deviation be recognised as a calibration problem rather than a process problem.

The PLC.net processes the readings in the sensor and outputs them over LAN: as Modbus TCP registers or as JSON over HTTP. Several measuring channels and lamp assignments are provided for, so a system with several emitters can be mapped over one network. For evaluation without a control system, the integrated web server exports the data as CSV and shows a run-time chart; the calibration uncertainty is typically 4.5 to 6.0 % (k = 2).

The calibration certificate states the expanded calibration uncertainty with k = 2; for the PLC.net sensors 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.

A UV sensor with an Ethernet (LAN) connection is suitable for the continuous monitoring of UV processes in automated systems, test benches, and industrial production environments. Ethernet communication allows measured values to be centrally recorded, documented, and integrated into control systems.
 

Integration into PLC systems is achieved via Modbus TCP. The sensor value is provided as a Float32 number in mW/cm². In addition, the wavelength and status can be read via registers.

DHCP server mode can be enabled using the built-in button. The sensor then provides a direct connection for a laptop and can be accessed at the IP address 192.168.100.1.

The HTTP interface allows direct access to current measurement values and device information over the network. The JSON output simplifies integration into customer-specific software, data loggers, test benches, and quality assurance systems.

The built-in web server allows measurement data to be exported as a CSV file. This enables measurement series to be documented, archived, and further processed in external analysis systems.

Scope of delivery: the PLC.net sensor and the factory calibration certificate, on request with an ISO 17025 calibration certificate. Please state the required spectral range with your order.

Accredited calibration to ISO/IEC 17025 in our own calibration laboratory. On delivery the sensor is already factory-calibrated.