Mach 3, Plain Jane printer port setup on a lathe. Hall sensor on the spindle to read RPM.
My RPM Dro's have started reading huge numbers. I'm talking in the millions and tens of millions, flashing crazily.
After chasing my tail looking for a setting that got inadvertently changed or a problem with the electronics, I finally realized the Dro's are reading correctly if you just look at the first four digits.
So I put a different screen set in and same result. I looked at the screen set in MachScreen and the Dro is definitely set to four places with zero trailing.
I'm out of ideas.