When you place the tensiometer on a spoke, it’s ideal if the tool reads zero but sometimes that doesn’t happen because of the spoke itself — they’re not perfectly round. If you don’t zero the tensiometer, you introduce error into your readings. Zeroing the tensiometer is easy but you experience a delay while it resets and it requires the use of both hands. In short it takes a bit more time.
With the introduction of the data cable I had the idea of skipping that step by doing the zeroing in post-processing instead. How does it work? Suppose you place the tensiometer on a spoke and it reads 0.01. Instead of zeroing the tensiometer, send that reading to the software by pressing the foot pedal or send button on the data cable. The software understands this to be a baseline reading so it pops up a dialog box with the initial value and prompts for the final reading, which you send in the same manner. Then the net value is calculated, the spoke tension graph is updated and you carry on with the next spoke. At no time do you touch the keyboard or mouse on your computer so the workflow is very smooth. I’ve built several wheels this way and it becomes second nature.