Further to the discussion of V to I converters it seems that the Howland Circuit is a pretty good fit for our needs. It only uses one opamp and some resistors and a few caps ( depending on your application needs) We would recommend this circuit. There is a detailed expose of this block from TI available publicly on the web. For more tech info and info about Signal Processing Group Inc, please visit our website ( under construction) at www.signalpro.biz.