Activating A Channel - GE DigitalFlow DF868 Programming Manual

Activating a Channel

Procedure Options
Programming Site Data
ACTIV
The submenu permits selection of the desired measurement
method. While following the programming instructions, refer to
Figure A-1 and Figure A-2 in Appendix A, Menu Maps.
ACTIV
1. Enter the submenu by pressing [F1] at the User Program
prompt.
[F1]
2. Press to activate the channel in
activate the channel in
Note: The current status of the meter is displayed in the bottom line
of the prompt area.
The Model DF868 flowmeter can take measurements in two different
ways:
•
The Correlation Transit-Time
transducers (either wetted or clamp-on) with each transducer
alternately sending and receiving coded ultrasonic signals through
the fluid. When the fluid is flowing, signal transit time in the
downstream direction is shorter than in the upstream direction; the
difference between these transit times is proportional to the flow
velocity. The DF868 measures this very small time difference and,
using various digital signal processing techniques combined with
programmed pipe parameters, determines the flow rate and
direction.
®
•
The TransFlection technique uses two transducers. One
transducer shoots thousands of grouped ultrasonic pulses in very
rapid succession. The pulses bounce off "scatterers" in the liquid
(bubbles, solids, or liquid droplets) and are reflected back to the
other transducer. Each received pulse group receives a "snapshot"
of the flow. By comparing all snapshots and averaging out objects
that do not appear to move with the flow, the DF868 can determine
flow rate and direction.
Note: If a customer has not ordered the DF868 with TransFlection
TRNFL
mode, the
To leave the User Program and return to measurement mode, press
[EXIT]
on the keypad. If changes have been made in any of the
submenus, the program will ask if you wish to save the changes. Press
[F1]
to return to measurement mode without saving the file or press
[F2] SAVE
to enter the submenu.
Note: See the
SAVE
submenu section on page 1-52 of this chapter for
more information on this function.
Transit-Time
TransFlection
mode.
™
technique uses a pair of
option does not appear.
March 2008
mode, or [F2] to
1-9