Rockwell Automation 1771-CFM,D17716.5.99 CONFIGURABLE FLOWMET - Manual (Page 16)

1–6 Overview of the CFM Module
Publication 1771Ć6.5.99 - December 1995
Using a Prover
A prover is used for the calibration of liquid meters in custody
transfer applications. This calibration is done by comparing a
metered throughput to a known volume in the prover. The number
of pulses accumulated (Prover Total Count Value), while the
spheroid moves between two detectors, is then compared to the
predetermined volume of the prover section to ascertain the
meter factor.
If you are using the Totalizer or Nonresettable Totalizer mode for
capturing meter counts during a prover calibration, you have the
option of selecting either of these types of provers:
detectors
spheroid
19884
unidirectional Ċ the CFM module:
• begins counting when the spheroid passes the
first detector
• stops counting when the spheroid passes the second
detector (Prover Total Count Value is updated at
this time)
bidirectional Ċ the CFM module:
• begins counting when the spheroid passes the first detector
• stops counting when the spheroid passes the second
detector (Prover Total Count Value is updated at this time -
intermediate value returned)
• continues counting when the spheroid returns past the
second detector
• stops counting when the spheroid returns past the first
detector (Prover Total Count Value is updated at this time)
Storing Current Count Values
If you are using the Totalizer or Nonresettable Totalizer mode and
you are not using a prover, you can use the gate input to store the
current count value of any (or all) of the four input channels.
The current count value of each channel is placed in a separate word
in the BTR file (Store Count Value). The Store Count Value will
remain in the BTR file until a new trigger pulse is received at the
gate input. The Store Count Value is then updated to reflect the
new value.