105 XFC G4 2103335 Rev AB
5.7.8 Reset Volume
When the volume accumulator is reset the flow computer will:
— Store time, date and previous accumulated partial calc periods volume into the historical record file
— Zero the remaining partial calc periods accumulations.
— Complete all computations for the present flow file daily record.
— Begin a new flow file daily record.
— Zero total volume accumulator and log the event with an accumulator value before zeroing out accumulator.
IMPORTANT NOTE: Since the flow computer volume calculations are made each vol calc period, any changes
you make during the period would affect the volume calculations (such as changing the orifice plate size) and be
introduced into the calculations. To avoid introduced errors, it is recommended that Reset Volume command be
used. This command forces the flow computer to perform volume calculations for the elapsed time since a previous
volume calculation was made. A new partial period volume is added to the volume accumulator, which is logged as
an event before it is reset to zero (0).
5.8 Startup the flow computer
5.8.1 Put the flow computer on-line
To put the flow computer on-line:
IMPORTANT NOTE: To avoid a calibration shift, carefully follow these instructions.
Open both bypass valves
Close the vent to the atmosphere valve. This stabilizes the pressure on both sides of the cell.
Slowly open the high side orifice tap valve from the meter run.
Slowly open the low side valve.
Close both bypass valves once both the high and low sides are completely open.
The flow computer is on-line.
5.8.2 Setting flow computer temperature calculation
The flow computer temperature calculations can be set to the following conditions:
— Selection of Fixed Temperature Used in Calculations—causes fixed temperature to be used in flow calculations.
— Selection of Fixed Temperature and RTD Installed—will record RTD temperature while using fixed temperature in
calculations.
— Selection of RTD Installed and not use Fixed Temperature—measures and uses RTD temperature in calculations.
However, if a temperature error occurs such as an A/D error, the Fixed Temperature will be used for calculations.
IMPORTANT NOTE: Selecting RTD Installed only, does not force the unit to use the flowing temperature in its
calculations. You must turn off the Fixed Temperature selection.
5.8.3 Volume reset
Since the flow computer volume calculations are made each vol calc period, any changes you make during the period would
affect the volume calculations (such as changing the orifice plate size) and be introduced into the calculations. To avoid
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