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Enter the following fields:
Instrument Name
--a user-defined label for the instrument
Driver Type
--select from picklist of known analyzers
Modbus Code
--also known as the
Modbus Device ID
, this ID is set in the analyzer,
and is some value from 1-255
Modbus Command Type
--defines which Modbus command is used to read data from the
analyzer (3 for TECO, 4 for API, consult instrument documentation for other brands)
Poll Interva
l- how often data should be requested from the instrument, in tenth of a
second increments. Generally, a rate of 2-3 seconds is recommended for most analyzers.
TCP Address
--IP address of the instrument, as viewed from the logger’s perspective
TCP Port
--Port used by the instrument for Modbus requests, usually “502”.
Timeout (MS)
--Designates the time the logger will wait on an instrument for
a Modbus response. Typical values are 250-750 MS, if needed, for an analyze missing
readings occasionally.
Modbus channels in the 8872 will use the
Modbus Scaling Factor
to convert floating point
data from the instrument before using it in averages, calibrations, etc. This can be used to
convert an analyzer that only provides PPB data on the Modbus link to PPM data, or similar
conversions. This approach is preferred over
Analyzer Units
in the logger, since the
Analyzer
Units
conversion only takes place on averages and calibration data, but causes inconsistency
with other logger configuration settings (alarm limits, calibration expected values, etc., and can
cause issues with a synchronized Central.).
Agilaire 8872 Manual
Chapter 2 Configuration
