PEMs have a feedback circuit to help control thermal stability. In addition, we recommend a 15 minute warm up time for the PEM to reach resonance equilibrium and stabilize before measurements are taken. However, if there is a rapid or large change in ambient temperature, it is possible there will be a slight drift associated with the thermal change. For this reason Hinds Instruments has recently introduced the PEM-ATC, a PEM with Advanced Thermal Control. This optional accessory provides two heaters controlled by a PID controller to make the PEM stable to within 0.5 C which holds the PEM retardation value stable to 0.02%. Please contact Hinds Instruments for more information on this new product.
