2-31
1010PVNFM-3A
Section 2
ZeroMatic
TM
(not present in MultiPulse operation)
When ZeroMatic
TM
is invoked the flowmeter first performs the same analysis as described
above in the AutoZero routine. However, after this analysis is complete the flowmeter contin-
ues to interrogate the pipe wall signal and update the zero offset value under normal opera-
tion, such that the flowmeter dynamically compensates for changing conditions which would
normally result in zero drift. ZeroMatic
TM
will only operate with the transducers mounted in
the Reflect Mode configuration and is recommended for applications which experience large
temperature extremes.
NOTE: Invoking ZeroMatic
TM
will clear any existing “fixed” or memorized zero offset.
If any zero offset remains after flow is stopped, an Actual Zero can be per-
formed without interrupting ZeroMatic
TM
operation. To disable ZeroMatic
TM
,
invoke it again, but then press <Left Arrow> to abort the installation.
NOTE: The ZeroClr command only resets the memorized zero offset registers not
those set when the AutoZero routine is invoked.
NOTE: Flow must be stopped with the line blocked (if possible) before invoking this
function.
To invoke Actual Zero:
Access the [Zero Flow Adjust] option list by pressing
ENT
ENT
Press . A pop-up window prompts you to set the current flow rate (in selected
rate units) to equal zero (0.000).
NOTE: If a flow offset is desired (i.e., to test analog outputs) then press <Right Arrow>
to enable numeric entry.
Press to start the Actual Zero process.
When you send the command, the flow computer analyzes the current flow rate for up to sixty
seconds, 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 Actual Zero
ENT
Using ReversaMatic
TM
If site conditions do not permit stopping the flow rate at the mounting location, and you do not
know the current flow rate, then you can use the ReversaMatic
TM
routine to establish the zero
flow level. You should perform the ReversaMatic
TM
procedure as quickly as possible to ensure
that the flow rate remains constant throughout the procedure.
To invoke ReversaMatic:
l To access the [Zero Flow Adjust] option list press
l Move the cursor to [ReversaMatic]. Press to invoke the routine.
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