Due to the physical behavior of their structural characteristics the functional parameters of low-pressure mercury vapour discharge lamps, are strongly depend on the ambient temperature. In case of fluorescent lamps, the main emphasis among electrical parameters is put on power, while among light-technical attributes, luminous flux comes to the front. The main requirement of launching a product is to meet the relating standards.
The IEC60081 standard defines 25°C environmental temperature for the measurement of electrical parameters. The luminous flux should be measured under the same circumstances, but, according to standard, manufacturers should declare a rated value assuming 35°C environmental temperature.
Because of the above described requirements it’s recommended to record the luminous flux (and other electrical parameters) as a function of ambient temperature on a wider range. The slope of temperature rise is determined by a recommendation of PRESCO [PRESCO(RTK)037].
Instruments need to be selected and testing procedure have to be defined to meet the requirements as defined in the recommendation. In case of linear fluorescent lamps these tests require long time, so it is recommended to create an automatic measurement control program, which allows human power/resource to be eliminated during the entire period of testing. Human presence is only necessary to condition lamps, initiate the measurement process and to evaluate the results. The duration of the test is longer than that of the shift, but automatisation gives the opportunity to switch off the lamp and shut down the devices without human intervention. Energy can be saved and the incidence of service accidents may be decreased.
The LabView development enviroment is the optimal choice to create the control-software, because it highly supports the actuation of instruments. It simplifies not only the programming of chain-attached devices through GPIB (IEEE488) ports, but also data query and storage.
After the development and installation of the new measurement system it is essential to check the reproducibility of measurements and the validity of results. Plenty of measurements are needed to be carried out to verify the process.