4-29
1010GCNFM-3C
Section 4
ReversaMatic
This routine involves swapping the Up and Down transducers on the pipe (while keeping the cables
attached) such that the difference in the transit-time change represents the zero offset. The fixed zero
offset value is stored in memory in the same manner as described in Actual Zero. This routine would
generally be used whenever flow cannot be stopped and the transducers
cannot be mounted in the
Reflect Mode configuration. Flow must be stable during the entire process.
ZeroMatic
When ZeroMatic is invoked the flowmeter first performs the same analysis as described above in the
AutoZero routine. However, after this analysis is complete the flowmeter continues to interrogate the
pipe wall signal and update the zero offset value under normal operation, such that the flowmeter
dynamically compensates for changing conditions which would normally result in zero drift. ZeroMatic
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 will clear any existing “fixed” or memorized zero offset. If any zero
offset remains after flow is stopped, an Actual Zero can be performed without inter-
rupting ZeroMatic operation. To disable ZeroMatic, 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.
Using Actual Zero
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
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.
ENT
ENT
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