Technical data

2. Start the calibration by clicking Start Zero. The calibration will start and run for the

period of time set in Zero time.

The average flow velocity is the value used to adjust the FwdA0 and RevA0

coefficients in the meter so they remove the offset flow under no flow conditions.

The Estimated maximum deviation is also calculated to help verify the meter is in no

flow and is used to set pass/fail criteria for the calibration.

An error will be generated if the Estimated maximum deviation is greater than 0.002

ft/sec or 0.0006 m/sec.

4. Once the calibration completes and no errors were encountered, click Write to Meter

to send the changes to the meter.

If errors were reported after the calibration, the calibration cannot be written to the

meter

5. If you selected to generate a report, Daniel MeterLink displays a dialog asking you if

you want to display the report once created.

6. Click Stop Zero, at any time during a calibration, to abort the calibration.

7. Click Discard once a calibration completes with no errors, to cancel the calibration

and setup the dialog to perform a new calibration.

8. Click Close to close the Zero Calibration dialog

4.1.7 Triggered Delta Volumes

The "triggered delta volume" feature provides the ability to measure total liquid flow

volume between two successive external event triggers.

To trigger an event, set the DoUpdtTrigDeltaVols data point to TRUE. This causes the

meter to save the current accumulated flow- and base-condition volume values (forward

and reverse). The meter then calculates the difference between these values and the

corresponding values saved from the previous event trigger. Finally the meter writes the

delta volume values to the appropriate data points (TrigDeltaPosVolFlow and

TrigDeltaNegVolFlow) and sets the DoUpdtTrigDeltaVols data point to FALSE to clear the

trigger and indicate the calculation completion

The triggered delta volume functionality is retained across power cycles as the

accumulated volume values at the last event trigger are saved in non-volatile memory.

The delta volume data points are stored internally in non-volatile memory as double-

precision floating point numbers. The delta volume data points can be read via Modbus as

either 32-bit floating point values or as integer values (using the [overflow, lower] LONG

Suggested User Access Logic

The following pseudo-code demonstrates the logic to access the triggered delta volume

functionality:

Daniel Liquid Ultrasonic Flow Meters calibration and configuration parameters

Operations 39