Hi Vince,

I could tell from your post on the NSRCA list you understand hysteresis, but I thought I'd try to upload a sketch that might make it clear how it works in the 14MZ. Without hysteresis we get a linear plot of servo position vs. stick position that is a single straight line that goes through zero-zero on an x-y plot. With hysteresis we get a loop as shown in the sketch. There are two parallel lines both of which are displaced from zero-zero. To see what happens let's start with the stick moved to the left with the servo positioned at the left defined by point 6. As we move the stick to the right. towards neutral, the servo holds the left position until we get to the right hand line and then it starts moving towards neutral but notice it is still to the left when the stick gets to neutral at point 1. the servo doesn't get to neutral until the stick is at point 2. As we continue to go right the servo follows right but when we reverse stick direction at point 3 the servo holds that position until we get to point 4. Once again when the stick gets back to neutral the servo is still lagging and is now right of neutral at point 5. So we can have two servo positions for the same stick position depending on which way we approached neutral. In real life it is near impossible to keep going in one direction unless you move the stick fast and you end up toggling back and forth between the two lines as you move the stick slowly.

With the hysteresis set to max (32) I measured about 8 microseconds (change in pulse width to the servo) between the lines so the neutrals at point 1 and 5 would be 8 microseconds apart. How this would affect your elevator trim depends on you set-up but it could be significant. I'd like it to be zero so I won't be adding hysteresis to get good neutrals. I may try it to see if I like the feel but it seems illogical to me.

Hope this helps and hope the sketch loads. If it doesn't please tell me how to do it.

Jim O