Appendix A. Measurement ConsiderationsModel PM880 Portable Hygrometer User’s Manual 175Appendix A. Measurement ConsiderationsThere are a variety of environmental and installation factors that can affectmeasurements. These factors should be discussed with a GE applicationsengineer or field sales person by the time you receive the PM880. However,if you decide to add additional measurement sites, this section containssome basic guidelines for selecting a measurement site and constructing asample system. This section includes the following:• Choosing a Measurement Site - see below• Moisture/Temperature Probe Considerations - page A-176• Sample System Guidelines - page A-179A.1 Choosing a Measurement SiteYou should have discussed environmental and installation factors with a GEapplications engineer or field sales person by the time you receive thePM880. The equipment should be suited to the application and installationsite.• Choose an installation site for the probes and sample systems that is asclose to the process line as possible. Avoid long lengths of connectingtubing. If long distances are unavoidable, a fast sampling by-pass loop isrecommended. Do not install any other components, such as filters,ahead of the probes or sample system unless instructed to do so by GE.• Observe all normal safety precautions. Use the probes within theirmaximum pressure and temperature ratings.• Locate the electronics unit away from high temperatures, strongelectrical transients, mechanical vibrations, corrosive atmospheres, andany other conditions that could damage or interfere with the meteroperation.
