User's Manual

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1010NFM-3JSection 2
Important Note: A caution on the use of upper and lower flow limits (used to prevent flow mis-registra-
tion) prior to using the Reversal Zero technique (Reversamatic): If the negative flow rate that the meter
reads in the step during which the transducers are reversed is more negative than the lower flow limit,
the meter will re-register positive and the Reversal Zero cycle will thus be corrupted.
Therefore, postpone the installation of upper and lower flow limits until the reversal zero procedure is
executed successfully. For pipes that combine large diameters with very high flow velocities, it may be
necessary to move the upper and lower flow limits out of the way until the reversal zero is completed.
Moreover, pipes of this size frequently have excellent intrinsic zero performance and may not even
need zeroing.
When you send the command, the flow computer analyzes the current flow rate for up to sixty sec-
onds, integrating (averaging) the data for the best zero correlation. During this time, the menu prompt
at the top of the display screen shows a timer that counts from zero to sixty. You can allow zero
averaging for the entire period, or cancel the process at any time by pressing the <ENT> key. This
controls the amount of data the meter averages to obtain a zero level.
Using ReversaMatic
If site conditions do not permit stopping the flow rate at the mounting location, and Reflect Mount is not
possible, then use the ReversaMatic routine to establish the zero flow level.
To invoke ReversaMatic:
z To access the [Zero Flow Adjust] option list press
z Move the cursor to [ReversaMatic]. Press to invoke the routine.
z The meter begins to measure the positive flow rate. “Positive” flow refers to flow moving from
upstream transducer location to the downstream transducer location. Note top prompt line shows:
Reversamatic Action
z Upon completion, the meter beeps and the display screen shows:
Reverse Xdcrs / Press ENT.
z Now remove then remount the upstream and downstream transducers in their reversed positions.
Mount the Up transducer (without removing its cable) in the Down transducer/cable location. Mount
Down transducer with its cable in the Up transducer/cable location. When remounting the trans-
ducers, couple them to the pipe properly. Press <ENT> (after re-installing the transducers).
z The flow computer measures the negative flow rate briefly, then beeps and repeats the
Reverse Xdcrs / Press ENT prompt.
z Now remount the transducers for normal operation (in their original orientation). When remounting
transducers, couple them to the pipe properly. Press <ENT> (after re-installing the transducers).
This completes the ReversaMatic procedure. The system’s zero accuracy will be very close to that
obtainable using the Actual Zero method, providing flow remained constant during this procedure.
ENT