Real-Time Data Management
In a custom measurement/data-logging system the actual sensors may seem like the most challenging part of the system, however in many cases dealing with the data management can often be a much larger part of producing a successful system. This is particularly apparent when working with high sample rates or multi-channel systems as the amount of data and bandwidth required can get large very quickly. Below we provide a brief overview of some of the main elements which must be considered for a real-time measurement system.
Dotstar Design have a lot of experience designing bespoke solutions to meet customer's measurement requirements. We can help you to design the best solution for you whether that involves a full custom electronic design or combining off-the-shelf products to meet your needs.
Once measurement data has been captured often further processing is required. This may be as simple as averaging multiple samples to reduce noise in the data or could involve calculating higher order effects often including combining results from multiple sensors.
Often industrial measurement and test systems need to measure the same parameters for many different "channels". Managing these channels can be very important, particularly ensuring measurements are synchronised. A production test station might need to test several identical units at the same time, recording the results for each unit and allowing the tests to contimue for some even if some units fail.
For the measured data to be useful to the user it most often needs to be available on their computers. Getting the data from the sensors to the computer can be acheived in many different ways, with the best solution being very application dependant.
In a multi-channel system often this data transport is split into multiple stages, firstly combining the data from each channel before finally transferring the data to a computer.
Depending on the data rates and locations of measurement systems different solutions can make more sense. Standard wired solutions such as USB and ethernet provide a good level of data integrity and bandwidth. Where sensors must be located over larger areas wireless protocols can be implemented. For applications requiring very high bandwidth interfaces like PCIe can be considered.
Whatever protocol/interface is used for transmitting data it is important to understand and develop a solution which ensures data integrity and avoids loss of any measurements throughout the system. Often you cannot guarantee data will be transmitted over an interface correctly everytime, in these situations techniques must be used to identify errors and either correct any faults or ensure data is retransmitted.
Dotstar Design have worked with several customers to both develop systems using standard interfaces such as USB, ethernet, PCI and custom wireless systems. We have also designed hardware using a custom interface to combine measurements from multiple seperated channels, by developing the embedded system and software together we were able to guarantee data cannot be lost of corrupted.
Many different methods can be used to store measurement data. To choose the best approach it is important to look at the amount of data being stored, the availability required (will multiple users needs to access the data simultaneously), how long the data should be stored for, how important it is to avoid data loss and how the data will be backed up.
Data can simply be exported to CSV file, which can easily be opened in standard spreadsheet software. Alternatively data can be written directly into specialised database on customer's servers, this provides a lot of flexibility for managing data retention and duplication to ensure no data is lost.
With Dotstar Design's experience developing both hardware and software we are able to work with our customers to develop a custom solution which integrates with the customer's working environment providing a solution which is easy to use and reliable.
Once the data has made it from the sensor to the users computer to make the data useful it is important to be able to view and analyse the measurements. Depending on the application users will have different requirements on how measured data must be used.
Dotstar can develop custom software to provide the data in a format most useful for the user. In previous projects we have developed both windows applications with custom graphing tools which connects to USB data logging device as well as a browswer based analysis application which is available accross the customer's network accessing data from a centrally served database.
In other applications the customer may want to view data in industry standard data tools or integrate with existing systems. For these applications it is important to ensure the data is available in the correct format for ingesting into these prebuilt tools, this can involve working with the data storage solution or developing custom software to integrate with these tools.