DE10135278A1 - Procedure to detect irradiation intensity and radial density in UV measurements - Google Patents

Abstract

Signal from photodiode is amplified, converted by voltage/current converter (I/U), digitized by A/D converter (ADWandler), processed in microprocessor and put in required protocol. Microprocessor EEPROM stores calibration data and other data. Interface to bus system is provided. Variable amplification of voltage/current converter allows A/D converter to be operated in optimal work range. Independent claim included for arrangement to measure intensity of rays and radial intensity.

Description

The invention relates to a method and an arrangement for measuring Irradiance and radiance in UV measurement technology, in which generates an electrical signal to a sensor and in an evaluation unit is processed.

It is known in UV measurement technology to measure irradiance levels and radiance sensors with a voltage or current interface use.  

According to DE 196 22 074 is a method and a device for measurement known from UV radiation in tanning devices, in which a relative spectrum the light source is recorded, with a sensor a local Intensity distribution of UV radiation is measured on the tanning device, a location-independent, absolute spectrum from the relative spectrum and the local intensity distribution is calculated and the calculated, location-independent absolute spectrum arithmetically with an erythema function is weighted.

In order to be able to carry out absolute measurements in mW / cm ² , it is necessary to calibrate the sensor to the final value of the associated interface. Depending on the application, a large number of differently calibrated sensors or current and voltage interfaces are required for this. It is particularly disadvantageous that these standard interfaces do not allow the entire linear range of the sensor to be transmitted. Si or SiC photodiodes are used as sensors for this.

The methods known in the prior art for detecting UV irradiance and radiance have the following disadvantages in particular

• 1. It can only be part of the linear working range of the receiver diode be exploited.
• 2. Only final values can be realized in the final value calibration.
• 3. A separate calibration is required for each permanent application  Sensors required, so that a high cost of materials and costs for warehousing arises.
• 4. The connected evaluation and display system must be connected to the Sensor end values can be adjusted.
• 5. The system has a high susceptibility to faults.
• 6. Only short cable lengths can be implemented.

The invention has for its object a method and an arrangement of the type mentioned at the beginning, with which a large working area of the Sensor is detected with high accuracy and that with little effort requires.

According to the invention, the object is achieved by a method which the in Claim 1 and with an arrangement which specified in claim 2 Features contains, solved.

Advantageous refinements are specified in the subclaims.

The solution according to the invention is characterized by a number of advantages. These include in particular:

• - The signals are digitally transmitted,  
• - The measuring amplifier can be integrated in the sensor or directly on the sensor become,
• - The measuring amplifier can be made switchable, so that the entire linear working area of the photodiode can be covered.
• - For converting signals and processing, AD converters and Microprocessor to be integrated.
• - A standard interface can be used, e.g. B. RS 485, RS 232, RS 422 or fieldbus systems.
• - It is possible to add non-volatile memories for storing calibration values integrate.
• - Suitable software can be created to operate the arrangement.
• - The measured radiation values can be recorded in suitable protocols (e.g. ASCII) are output.
• - Only one calibration is required for all sensors.
• - A larger number of sensors can be connected in parallel.
• - The digital interface ensures high immunity to interference.
• - It is possible to use one sensor for all applications, so that no sensor variations are required.
• - Since no signal to be disturbed leaves the sensor housing, there is a high one Analogstörfestigkeit.
• - No adaptation is required for successor systems.
• - The adjustment of the sensor is easily possible using a computer and can optionally also be automated.

The invention is explained in more detail below using an exemplary embodiment. In the accompanying drawing:  

Fig. 1 shows the circuit arrangement of the sensor and

Fig. 2 is a schematic representation of an arrangement with several sensors.

As can be seen from FIG. 1, a signal generated by the photodiode FD is amplified and converted in the sensor by means of an I / U converter I / U with variable gain. The signal is transferred to the digital level by an analog-digital converter ADW and processed here according to the calibration and the set gain in the microprocessor µPC and finally brought into the appropriate protocol form. The sensor is connected to a bus system on which a connected device can request the determined data via the SS interface (e.g. RS 485). The variable amplification of the I / U converter ensures that the ADW analog-didital converter is always operating in the optimum working range, which ensures maximum accuracy. The connected EEPROM is used to store calibration data, serial numbers, production data, quality data, address etc.

FIG. 2 explains an example of a complete system in which a large number of sensors S ₁ . , , S _n are connected in parallel, an address being adjustable for each sensor. The sensors S ₁ . , , In the example shown, S _n monitor a system in which the flow rate of a flowing liquid is measured with an incremental flow meter IDM and its state with the aid of sensors S ₁ . , , S _{n is} recorded and evaluated. For this purpose, they interact with a monitoring unit ÜE. The individual elements are coupled via the data lines A and B or RXD, TXD and the power supply lines U _n and M and can be connected to a display device A of a programmable logic controller PLC, the personal computer PC and the controller St.

LIST OF REFERENCE NUMBERS

FD photodiode
I / UI / U converter
ADW analog-to-digital converter
µPC microprocessor
SS interface
V amplifier
IDM incremental flow meter
PLC memory program system
PC personal computer
TXD transmission line
RXD receive line
U _n

Operating voltage line
M ground line
ÜE monitoring unit
A display
St control
S ₁

, , , S _n

sensors

Claims (4)

1. A method for measuring irradiance and radiance in UV measurement technology, in which an electrical signal is generated and processed with a UV sensor, characterized in that the signal in the sensor by means of an I / U converter (I / U) is amplified and converted with variable gain, then transferred to the digital level by an AD converter (ADW) and processed here in accordance with the calibration and the set gain and brought into a corresponding protocol form. 2. Arrangement for performing the method according to claim 1, characterized characterized in that the sensor contains a photodiode (FD), which has a I / U converter (I / U) and an analog-digital converter (ADC) on one Microprocessor (µPC) is connected to an interface (SS) Device can be connected to request the data. 3. Arrangement according to claim 2, characterized in that on Microprocessor (µPC) an EEPROM for storing calibration data, Serial numbers, production data, quality data, address etc. is arranged. 4. Arrangement according to claim 2 or 3, characterized in that a A large number of sensors are arranged in parallel.