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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:
zTo access the [Zero Flow Adjust] option list press
zMove the cursor to [ReversaMatic]. Press 
ENT 
to invoke the routine.
zThe 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
zUpon completion, the meter beeps and the display screen shows:
Reverse Xdcrs / Press ENT.
zNow 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
zThe flow computer measures the negative flow rate briefly, then beeps and repeats the Reverse Xdcrs / Press ENT prompt.
zNow remount the transducers for normal operation (in their original orientation). When remounting transducers, couple them to the pipe properly. Press <ENT> (after
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.
Important Note: A caution on the use of upper and lower flow limits (used to prevent flow
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
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.
