78 of 138 Inputs/Outputs Menu - Orbisphere 510/511/512 AnalyzersOperator ManualORBISPHERE6.5.2 “Tri Linear” Analog OutputThe "Tri-linear" output brings benefits over the “Linear output” discussed before. It isillustrated in Fig 6-4 below (4-20 mA output is shown, 0-20 mA or 0-5 V settings aresimilar).Compared to the “Linear” mode, the expected range of measure is Range 2. A Range 1and 3 are available to show the measures falling out of this Range 2, but normally at alower resolution. Expected measurements for the measured process are supposed to bein Range 2 most of the time, and in Range 1 or 3 occasionally (problems, calibration, linestop, etc.). The benefits are:• The PLC can compute the measurement over a large range (1, 2 and 3).• The PLC can compute a higher resolution signal for the expected measuringrange (Range 2: MH > M > ML).• Carefully selecting the set points allows for an individual resolution for each range,so a different resolution can be applied to Range 1, 2 and 3, allowing you to tailorthe analog output to the actual conditions.As before, the downside is that any measure below or over the Range 1, 2 and 3 willhave the same signal locked at 4 mA and 20 mA respectively, but Range 1, 2 and 3should cover a larger range than in the “Linear” mode. Settings must be made inbalancing these aspects.Fig 6-4: “Tri-linear” Characteristics Diagram (4-20 mA shown)SettingsFor each output, set MLL, ML, MH, and MHH to the current measuring unit (e.g. °C for atemperature output). When a compound unit is selected, the smallest unit will be used(e.g. ppb for a "ppm-ppb" compound unit). Also set AOL (Analog Output Low) and AOH(High) in mA (or Volts).
