1535 Relative Humidity Transmitter - Novatech Controls

!2.6 CONNECTING THE REFERENCE GAS (AMBIENT) TEMPERATUREAND DRIER TEMPERATURE SENSORSThe ambient temperature sensor is optional for indirectly heated dryers or for directly heated dryers where ambientair is used as a reference. It is essential if the installation is on a directly heated drier with process gas used for areference gas to the oxygen probe.For simply monitoring air temperature, mount the ambient temperature sensor in a protected position with plenty ofexposure to the air. The sensor is supplied within the relative humidity sensing enclosure. Refer to Figure 2.6a forconnection details.Figure 2.6a Connection of Ambient Temperature Sensor, AD590When used with a directly heated drier with process gas used for a reference gas to the probe, the installation musthave a reference gas cooler. This sensor is then used to measure the reference gas temperature after the cooler. Thereference gas sensor will be included in the cooler.The cooler will be fitted with a PT100 RTD sensor. It is necessary to use shielded, low resistance cable for thissensor (18 gauge or lower resistance). Compensation can be made for lead resistance. See section 5.5.15.PT100 RTD1.5k Ω8 RH -9 + 12 V10 AMB TEMP +11 AMB TEMP -Figure 2.6b Connection of Ambient Temperature Sensor, PT100 RTDNOVATECH HUMIDITY TRANSMITTER Page 23