GE DigitalFlow DF868 User Manual

Programming Site Data 1-9
March 2008
Entering Channel Data While following the programming instructions, refer to the menu map
in Figure A-1 on page A-1 or Figure A-2 on page A-2. After selecting
[F1]=CH1 (or [F2]=CH2) at the initial programming screen, the
following screen appears:
Based on the selection made above, proceed to the appropriate section
of this chapter for instructions.
Activating a Channel The ACTIV submenu activates a channel and selects the desired
measurement method.
1. To enter the
Channel PROGRAM menu, press [F1] or [F2] (depending
on the desired channel) at the
User PROGRAM prompt.
2. Enter the
ACTIV submenu by pressing [F1] at the Channel PROGRAM
prompt.
3. Press
[F1] to deactivate the channel, [F2] to activate Channel 1 in
Transit-Time mode, or [F3] to activate TransFlection mode.
The Model DF868 flowmeter can take measurements in two ways:
• The Correlation Transit-Time™ technique uses a pair of
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 the DF868 has not been ordered with TransFlection mode,
the TRNFL option does not appear.
Proceed directly to the next section to program the
SYSTM submenu.
Chan 1 PROGR Start ‰
Press the [←] and [→] keys and
a function key
[F1]-[F4] to select
the desired submenu. From this
screen, press
[EXIT] to return to
the initial User Program screen
shown on page 1-8.
Channel PROGRAM
status
ACTIV SYSTM PIPE I/O

GE DigitalFlow DF868 Specifications

General

Brand	GE
Model	DigitalFlow DF868
Category	Measuring Instruments
Language	English