Melanie, that looks almost the same as the one we're currently using. The biggest difference I see is that we originally used a CA5160E Op-Amp due to it high input impedance. We ended up switching to a CA3140E which was a lot cheaper. This circuit works good for us except we keep speratically frying Op-Amps. Not sure why but when the end product is about 2,000 miles away it makes for a tough on-site fix. Just wish we could fix out what was causing them to fail. They are decoupled with a 0.1uF capacitor, a diode on the output to prevent any kind of feedback and they still sometimes fail without warning.