Function clamp_relay_amplitude 

pub fn clamp_relay_amplitude(
    relay_amp_percent: f32,
    mv_ini: f32,
    mv_range_low: f32,
    mv_range_high: f32,
    compat: MrftCompat,
) -> f32

Computes the raw engineering-unit relay amplitude from a percentage of the MV range, and clamps it so neither relay step would drive the MV outside [mv_range_low, mv_range_high]. Pure port of CheckMVboundaries.