Reduction of pollutant emissions into the atmosphere
Enercat needed to optimize the supervision and control software of a test bench in order to increase the volume of tests while having a user-friendly and efficient graphical HMI.
Phalanx used the "Scan Mode" of the signal acquisition and generation module already present on a cRIO-9073 controller to increase the volume of tests. Improve the HMI by offering a new software design with custom controls and indicators.
Enercat is a company which develops and markets innovative technologies in the fields of the environment (development of technologies to reduce pollutant emissions into the atmosphere by catalytic means) and energy (production of hydrogen from natural sources). hydrocarbons, associated with the development of the fuel cell) - Valorisation of Renewable Energies.
Enercat, located in Ploemeur (Morbihan), called on our company Phalanx to improve the existing test bench carried out under LabVIEW for testing catalysts (see image 1).
A project for the environment
For several years, global warming has continued to increase: "Air and ocean temperatures, rising sea levels, carbon dioxide emissions, melting ice, [...]. Dozens of records have been broken on the fifty or so indicators presented in this State of the Climate in 2015. And most of them indisputably show "a trend towards global warming" "(Le Monde article, August 3, 2016). Corporate social responsibility is becoming a major concern for many organizations. This is why Phalanx wishes to engage in projects related to the environment with the aim of reducing greenhouse gas emissions.
This project concerning a company working in the environmental sector, on a test unit to evaluate catalysts intended to treat polluting emissions into the atmosphere, fits perfectly with this approach.
How Catatest software works
The bench consists of passing a fluid through a catalytic converter via the flowmeter control which serves as both a sensor and an actuator to regulate the flow. This fluid is then heated via heating shells (heating system surrounding the catalytic converter).
When the user launches the software, he arrives at the test page. It is from the latter that the user will control the flowmeters, the heating shells and start one or more recordings.
The operator can choose which flowmeters to activate: each flowmeter is independent and configurable. Different flowmeters can thus be used.
The shell temperature regulation is activated by the user for each shell present.
All the devices put into operation are easily identifiable on the HMI using LEDs.
Once the user has made a recording, he can, via the “Report” page, create an Excel file in which all the parameters of all the bench devices (flowmeters, saturator, shells) are recorded in order to have a report on the conditions of the experiment.
A safety is added to control the temperature and if one of the heating shells exceeds this limit, all of the activated regulations and flowmeters are deactivated. The user then sees a red LED appear on the HMI indicating the activation of a security. As soon as the temperature (s) have dropped below this limit, the operator can resume the tests in progress.
One of the big novelties was the implementation of temperature safety, putting the bench in a specific state (shutdown of all flow and heat regulations) if they exceed a maximum threshold. The user will be able to resume his test by pressing a button on the HMI only when the temperature drops below this threshold.
Another novelty was the use of the report generation functions to create a report from an Excel template file.
Save time: use of scan mode and network shared variables
This project was to be completed in 13 working days as specified by Enercat. The first idea in order to save time during program development was to limit the sending of data via communication methods between the different hardware levels. When writing the specifications, Enercat gave us the specifications for the acquisition and recording speeds, these were a maximum of 8 Hz for acquisition and 0.5 Hz for recording. In addition, the indicators present on the HMI should only display the last acquired values. These various factors have led us to choose the use of scan mode which, like the National Instruments advice, is sufficient for applications that require an acquisition speed not exceeding one hundred hertz. Thus, thanks to this method, we were able to avoid the development of FPGA code but also the implementation of communication methods between FPGA and RT.
As the data logging is one point every 2 seconds and the data is saved on the PC, we have opted to send the data via shared variables on the network. This method avoids setting up a network flow for sending all the data from the RT to the PC.
Ainsi, grâce à l’utilisation de méthodes développées par National Instruments sur leurs matériel et logiciels, le scan mode et les variables partagées sur le réseau nous avons pu réaliser le logiciel en temps et en heure tout en garantissant le respect des spécifications.
Real-time executable taking up little memory space
During the realization of this project, we had to face some challenges. One of the most important was the management of the memory available on the CompactRIO model that we had. The first solution would have been to choose a compactRIO with more memory. However, the purchase of new hardware was not considered. The solution adopted was then to customize the installation of software via MAX (Measurement And Automation) in order to use little memory space such as NI Scan Engine, NI RIO, NI VISA, Network Variable Engine, LabVIEW Real-Time. We had to be careful not to install some of the software dependent on those selected.
Thus, by custom software installation via MAX, we have succeeded in solving one of the major problems encountered during the integration at the client
Conclusion and perspectives
Thanks to the new software developed, the bench is durable and easily maintainable. In addition, we have added features that will allow better flexibility of the bench if necessary: possibility of entering a range of hysteresis for the activation of the relays managing the heating shells, possibility of specifying the input value of the saturator pressure .
Thanks to the operationalization of this bench, the test volume has been doubled.
Thanks to the ease of use of LabVIEW and the easy integration of National Instruments hardware, we were able to complete the bench in the allotted time (13 days) while respecting user needs.
