Yokogawa CA300 Series [CA320] Thermocouple Process Calibrator.The CA300 Series is a high accuracy source and measure portable handheld calibrator used to inspect and maintain the accuracy of control devices such as temperature controllers, temperature transmitters, temperature sensors and other process devices which are used in process plants, industry machinery, and manufacturing. Available in 3 models, the CA310, CA320, and CA330 provide an ergonomic and friendly user-interface making it easy to use