Hach Ultra ORBISPHERE 510, Руководство оператора

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78 of 138 Inputs/Outputs Menu - Orbisphere 510/511/512 Analyzers
Operator Manual
ORBISPHERE
6.5.2 “Tri Linear” Analog Output
The "Tri-linear" output brings benefits over the “Linear output” discussed before. It is
illustrated in
Fig 6-4 below (4-20 mA output is shown, 0-20 mA or 0-5 V settings are
similar).
Compared to the “Linear” mode, the expected range of measure is Range 2. A Range 1
and 3 are available to show the measures falling out of this Range 2, but normally at a
lower resolution. Expected measurements for the measured process are supposed to be
in Range 2 most of the time, and in Range 1 or 3 occasionally (problems, calibration, line
stop, 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 measuring
range (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 tailor
the analog output to the actual conditions.
As before, the downside is that any measure below or over the Range 1, 2 and 3 will
have the same signal locked at 4 mA and 20 mA respectively, but Range 1, 2 and 3
should cover a larger range than in the “Linear” mode. Settings must be made in
balancing these aspects.
Fig 6-4:
“Tri-linear” Characteristics Diagram (4-20 mA shown)
Settings
For each output, set MLL, ML, MH, and MHH to the current measuring unit (e.g. °C for a
temperature 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).