Think of the InqPortal History tab as a generalized and highly configurable history graph. It is conceptually similar to the Windows Task Manager’s Performance tab. It shows a running graph as a function of real-time data. It defaults to showing some of InqPortal‘s performance metrics. In the following case, we can see the Loop Frequency, Available Heap Memory and Supply Voltage and we track up to 60 seconds worth.
Default Configuration of the History Tab’s Data
What sets apart the InqPortal History is its configurability. From the Admin menu, select the Configure History… option. This will popup a simple, yet powerful configuration dialog. This will allow you to add your own project’s published variables and to adjust time base and accumulation properties. Let’s jump in to the options.
Your Published Variables
If you are not familiar with InqPortal‘s published variables, you might need to check out how to create them by either one of the tutorials: (Quickest, Quick, Verbose) or by the Reference page for the Sketch methods used to create them or finding the information on the App Tab. At the very least, you must have some published numeric data before you can display it.
Selecting Your Custom Published Variables
The top input is a free-from entry box. As the reminder instructions above it say, you simply add a descriptive title to go on your Y-axis and then add your published variable’s web ID. If you want to add another curve, you add another comma and then another title, web ID pair. You can add as many as you can tolerate the mess.
In example, if you are using the sample tutorials, that simulate a temperature gauge (using a trigonometry sine function) output going to the published Sine variable. You would simply add Temperature (degrees °C),Sine. Press the Configure button and you’ve now added your custom data to the system performance metrics.
Combining a Custom Published Variable with System Performance Metrics
Showing / Hiding System Metrics
It’s as simple as checking / un-checking the boxes directly under the free-form entry box.
Keep Duration
These two entries allow you to set the total duration in seconds, minutes, hours or days. Any data older than the selection is not kept.
Averaging Points
The system metrics arrive every second. For the current example showing a Keep Duration of 60 seconds, this logically says there will be 60 points for each curve kept in the graph. What happens if you were wanting to keep 24 hours worth. This would amount to keeping 86,400 data points for each curve. Since your client is likely running on a Windows PC or even a smart phone, this is really not an issue of storage. But it does become an issue of visualizing the data. Even with a 4K monitor, you only have 3840 pixels horizontally to show those 86,400 data points. You might want to set the Averaging Points field so that fewer points will be on the graph. If we have a nice 4K monitor, we probably could get away with using and average of 60. This way we’ll take 60 data points and find the average value and only plot the one point… coming out at one data point per minute for a total of 1440 being on the graph before falling off. This also makes sense from a practical standpoint… Sensors typically have some random noise in the data. Averaging 60 data points for every point plotted will smooth the results that actually would be more real-world realistic.
The same kind of philosophy holds if you have a very high rate output. Say… you’re outputting a value every 10 milliseconds and you want to show only one minutes worth. This would still plot 6000 data points. In this case you might want to adjust to average 10 points to plot every point.
As an example of the power of these capabilities, the following graph shows 70 hours of data from a weather station project which includes two temperature readings, a pressure reading and a humidity reading along with a 3 hour pressure differential. Each reading averaged data points and recording one point per minute for each curve.
Exporting Data
Seeing the graphs is one thing, but what if you need to do some real analysis and comparisons with other data? Using the InqPortal Admin’s menu option Export History Data, you can export the data in CSV format, ready to be loaded into your favorite spreadsheet.