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A project log for ReTest-yg

YG's own version of Mateng's ReTest, but with different features and a palindromic project number!

yann-guidon-ygdesYann Guidon / YGDES 11/09/2018 at 03:020 Comments

Given the new situation and hardware availability, what should it do and how should it work ? What is the characteristic that determines then binning ?

So far, I think that the meaningful data is the average between the open and closed voltages. The early measurements show that there is a significant variation of those characteristics and the operating margin is reduced when the max. release voltage in a group gets near the min. latch voltage of another relay, whose coil has characteristics shifted toward the lower voltages.

The algorithm I consider will take the dump of all the measurements, in the form of a file (in CSV or JSON) containing the min and max voltages, followed by the serial number.

From these values, calculate the average (or sum?) and difference (the margin).

Sort all the values by the difference, and remove the lowest ones (which provide the least operating margin).

Then sort all the values by the averages, such that bins can be easily made by splitting the list in roughly equal sub-lists.

And there you have it : a list of lists of serial numbers of the relays that will be soldered together.

For the 8×8-bits register set, that's 8 bins, and I suppose at least half of the measured relays will be rejected so more than 120 relays must be measured. The resulting sets will be more resilient to power supply variations.

Now I have to build the test rig, write the software, and get to work by measuring 4 boxes of relays...

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