Can you explain what was before Modbus? For e.g. contact closures can fuel level EMPTY or FULL. But it cannot tell fuel level at 37%. How were numbers represented/shared before Modbus?
It's not software, actually. It's a piece of plexiglass with LEDs around the rim. You then write on it with neon "chalk" dry-erase markers. The markers pick up the light from the LEDs. Once you're done, you just flip the video in software. I've had to learn to thoroughly clean it between shots, and to find a "hole" to talk through after I finish my drawing.
