Sean Thomas et al I switched over one Smt8 style sensor from Lvdt to Vrdt and incorporated a zeroing motor. I calibrated the vrdt and it was very linear. The sensor oscillates well without the Vrdt, so I know the spring is ok. My problem is when I put the metal strip between the vrdt coils the sensor won't center. It goes from one end to the other, no matter how slowly I try to center it. I took the feedback coil out of the loop during this adjustment. I thought the vrdt was magnitized so I touched the laminates and center strip with a soldering iron... no different. Any help? Btw.. when I put the feedback coil in the circuitry the sensor oscillates around the center position then gradually stops and slowly drifts to one end Regards Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>