Apologies for the lack of graphic detail, but this is what I have to work with:
Near the bottom we have "Angle". This is the input field I'd like to "restrict".
Firstly, I will be changing this to an integer, the above graphic doesn't show that correctly: Temperature/Elevation/Angle, but consider it done.
Whilst the Angle could be in the range of 0 to 360°, I'd like to restrict between 90 and 45. This may well be a good case for "Auto", so probably the "Key-Up" event?
Complicating that, there MUST be 2 characters input first, before an evaluation is made. I guess using the LEN function - within the key-up event?
Although, the "glaring" possibility is just to use the UPDATE button, which will/should evaluate ALL inputs anyway. But, I think that if the user enters two numeric characters, then a number over 90, should default to 90 and below 45 will default to 45. That is to say, when the user releases the key AND there are two digits, the evaluation is made.