Siemens SITRANS FUS1010 NEMA-4X/ IP 65 manual ReversaMatic, Using Actual Zero

Section 2 1010NFM-3J

Actual Zero

The “Actual Zero” function simply averages the indicated “zero flow” readings (over a user defined time period) then stores this average value in memory. Under normal operation the indicated flow reading is zero compensated by simply subtracting this memorized value from the uncompensated flow reading. Actual Zero is the most positive method for zeroing the system, however, flow must be stopped with the line blocked (if possible) before invoking this function. If stopping flow is not possible then an alternate zeroing method should be selected.

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 (not present in MultiPulse operation)

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 ENT . 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 ENT to start the Actual Zero process.

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