41Appendix A Optional AccessoriesA.1 Relative humidity/Temperature (RH/T) probeThe RH/T probe (refer to Figure 4 on page 10) monitors relative humidity (10% to 90%)and temperature (5 to 125 °F or –15 to 50 °C). The MET ONE 237 particle counterdisplays the reading and includes it in the internal particle count data record. Refer tosection 3.2.5 on page 12 for installation instructions.A.2 High-pressure diffuserThe high-pressure diffuser (refer to Figure 19) is connected to the sensor inlet tubing ofthe MET ONE 237 particle counter. The diffuser (permits direct sampling of pressurizedair at pressures from 30 to 150 psi.A.3 RS485 converterThe RS485 converter (refer to Figure 20) converts data from RS232 to RS485 format forlonger serial networking to a computer. Contact technical support for installation details.Figure 18 RH/T probe (Catalog No. 2080825)Figure 19 High-pressure diffuser (Catalog No. 2080372-6)Figure 20 RS485 converter (Catalog No. 2082383-2)