Linearity tests are done by specialized technicians nearly continuously for all the year.
The process consists in connecting the gas analyzer to the outlet of a gas divider, setting the wanted dilution and … waiting. Waiting time depends on the type of gas analyzer and on the sample composition, but generally is the longer time in all the working day.
When a stable measuring value is available, the operator gets the number and changes the dilution to check another point … and restart waiting.
This is why the software InfoCAP3000 did born: the activities of setting a step in a sequence, waiting longtime and getting an analyzer reading are perfectly done by a PC and associated program. The PC software send to the gas diluter the instruction about the wanted dilution, than knows which is the target result.
The gas divider receives the measured values of the gas analyzer through an analogic isolated interface and send them to the PC when requested. The PC is informed about the diluted concentration sent to the gas analyzer and about the analyzer measured value end than knows all what is needed to evaluate how much the response of the analyzers is complying with the measured composition.
The technician task is than concentrated in high value activities : setting the test procedure and controlling (signing) the PC report. Many kind of tests can be done with a diluter and a PC : Linearity, repeatability, sensitivity (having the right test gases) and also cross sensitivities. This last type of test is regularly done with BetaCAP60 diluters that can provide two independent dilutions. Somebody makes cross sensitivity test by changing the interfering gas and letting fixed to zero the measurand, but this method is not complying with norms.
THE THREE MAIN MODULES OF THE SOFTWARE
DATA BASE
It’s a memory space where all the hardware components (mainly reference test gases and gas analyzers are recorded in a relational way. Also software components, like Sequences, and Procedures are stored in the same data base.
Using a relational data base, the information can be retrieved easily, due to hierarchical data structure.
The sequence page include the list of elemental steps that are repeated each time it’s called. Some instruction “Implicit” are activated in all the sequences : as an example the frequent request of measured concentration to draw the trend of concentrations set by gas divider / measured by gas analyzer.
Procedure page informs the software about how the circuit is connected : which is the measuring analyzer, which is the reference test gas to be diluted, which the diluting gas, how analogical signals from the gas analyzer are connected (AI1, AI2 and AI3) and finally which sequence must be activated.
After that the test can start and can be monitored during his run. At the end it can be printed according with the wanted protocol.
