No, the software won’t allow you to go slower than 10%. I assume you did an INTERLOCK + TEST START. That is 25% of maximum speed. I’m surprised that the software will even let you enter in less than 25%. It’s been that way for decades though.
Well, there it goes another thing that I don't like about this Yaskawa robots.
Interlock + Test Start goes insanely fast on T1/Manual mode. I am using Interlock+FWD for low speed, but this way you can only appreciate the path on an step by step mode...
When testing on automatic mode, it allows you to go as slow as 10% (Utility > Speed Override). When you press shift+up/down, the over-ride speed goes 10,11,12,13... an so on, but it won't go below 10.
Thanks for your answer, I'll start praying to the programming gods for good luck!