Connecting Espruino to Excel

[espruino-discuss2]

Posted at 2014-11-25 by tage

Today I was working on a power converter where I am using my Espruino board to measure input and output voltage and current and also to generate some project specific control signals that make the power converter behave as I want it to.

I have my lab bench set up so that I control my instruments with Excel. The instruments are talking over GPIB and the setup allows me to quickly repeat a measurement I did months ago, with exactly the same test setup. So I can compare test results in a repeatable way. I can return to a design I did long time ago and repeat the tests and continue improving the circuit and compare performance.

The project I am working on right now requires a micro controller and I decide to try Espruino. This far, my experience has been quite positive and I am continuing this path. I decided to see if I could include my Espruino board into the Excel test setup. This turned out to be quite simple. If anyone is interested I can perhaps write a tutorial on how to do this.

[gfwilliams]

Posted at 2014-11-25 by @gfwilliams

Great, glad to hear it's working well!

Are you using Esprunio to connect to GPIB?

[espruino-discuss2]

Posted at 2014-11-25 by tage

Communication between Excel and my bench instruments is over GPIB but for the Espruino I am using the USB cable. It appears as COM12. In addition to Excel you will need to install IO Libraries from www.keysight.com/find/iosuite .
The attached screenshot shows data from Espruino on row 9 (cell A9,B9,C9,D9). Row 7 has data from my instruments. The graph in the lower right corner shows output voltage of the testobject as function of load current measured by a 34401 precision meter (blue) and same measurement from Espruino. I used a simple Median filter to remove measurement noise. You can see the 16.6mV steps caused by the 12 bit resolution when a measurement range of 68V is used. It should be possible to improve the Espruino filter to smooth the line.
The test object is a buck-boost converter that is capable of handling power flow in both directions, and I am adding digital control so I can demonstrate the function of the power stage.

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Attachments:

• excel.png