Emerson Daniel 3410 Series User Manual

3410 Series Gas Ultrasonic Meters Operations Manual Section 5: Calibrate and configure the meter
3-9000-777 Rev E January 2018
No wet calibration 49
5.1.5 No wet calibration
If no wet calibration is selected, then the wet calibration gas flow velocity is equal to the dry
calibration gas flow velocity.
5.1.6 Triggered Delta Volumes
The “triggered delta volume” feature provides the ability to measure total gas flow volume
(flow- and base-condition) 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, TrigDeltaNegVolFlow, TrigDeltaPosVolBase, and
TrigDeltaNegVolBase) 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
volumes 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 register pair in a
manner similar to reading the accumulated volumes).
Suggested user access logic
The following pseudo-code demonstrates the logic to access the triggered delta volume
functionality:
• I
NITIAL SET-UP:
Ensure Modbus units are set-up as desired: set Modbus register 10026 (
UnitsSystem) to 0
for U.S. Customary units or to 1 for metric units.
• P
ERIODIC LOOP:
Wait for external event for synchronizing the start of the meter delta volumes.
Send trigger Modbus message: set Modbus register 12199 (
DoUpdtTrigDeltaVols) to 1
(TRUE).
Read trigger Modbus register 12199 (
DoUpdtTrigDeltaVols) in a loop until it is read as 0
(FALSE) indicating that the delta volumes have been updated.

Emerson Daniel 3410 Series Specifications

General

Brand	Emerson
Model	Daniel 3410 Series
Category	Measuring Instruments
Language	English