Viatran IDP10-A, Инструкция по установке, калибровке и эксплуатации

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98MANALIDP10AV Rev. A 8/16/11
3. Each transmitter is factory calibrated to either a specified or a default calibrated range.
This calibration optimizes the accuracy of the internal digital value of differential pressure
over that range. If no range is specified, the default range is zero to the sensor upper range
limit (URL).
4. There is an independent trim on the digital-to-analog conversion stage. This trim
allows for slight adjustment of the 4 and 20 mA or 1 and 5 VDC outputs. This
compensates for any slight difference that exists between the transmitter output and
an external reference device which is measuring the output.
The trim does not affect the calibration or the re-ranging of the transmitter and
does not affect the internal digital value of pressure or the transmission or display of
measured pressure.
The trim can be done with or without pressure applied to the transmitter.
Notes for Electronic Version -A and -V
The transmitter data base has configurable values for both Lower Range value (LRV) and Upper
Range Value (URV). These stored values are used for two functions; defining the calibrated range
and re-ranging without pressure.
1. Defining the Calibrated Range
When either CAL LRV or CAL URV is initiated from the pushbuttons, the
transmitter expects that the differential pressure applied at the time the button is
pressed is equal to the LRV or URV value respectively.
This function trims the internal digital value of differential pressure; that is, it performs
a calibration based on the application of accurate differential pressures equal to the
values entered for LRV and URV in the transmitter database.
This function also sets the 4 and 20 mA (1 and 5 VDC for IDP10-V) output points;
that is, the 4 and 20 mA (1 and 5 VDC for IDP10-V) points correspond to the values
of LRV and URV in the database.
If the transmitter is configured for reverse range, the 20 and 4 mA (5 and 1 VDC for
IDP10-V) points correspond to the LRV and URV respectively.
2. Re-ranging Without the Application of Pressure
Since the transmitter continually determines an internal digital value of the measured
differential pressure from the lower range limit (LRL) to the upper range limit (URL),
the 4 and 20 mA (1 and 5 VDC for IDP10-V) output points can be assigned to any
range values (within the span and range limits) without application of pressure.
The re-ranging function is accomplished by entering new database values for LRV and
URV.
Re-ranging does not affect the calibration of the transmitter; that is, the optimization
of the internal digital value of differential pressure over a specific calibrated range.
If the re-ranged LRV and URV are not within the calibrated range, the measured values
may not be as accurate as when they are within the calibrated range.