Chapter 2. Initial Setup
26
DigitalFlow™ Multipurpose Ultrasonic Liquid Flowmeter Startup Guide (1- and 2-Channel)
2.6.4 Pipe Wall
5.
Enter the known thickness of the
Pipe Wall
, in the same units used for the pipe OD, and press
[ENT]
.
IMPORTANT:
Because the units can not be independently chosen for this parameter, the value must be entered in the
same units used for the pipe OD.
If the pipe wall thickness is not available, look up the value in a table of standard pipe size data (such as the GE
brochure
Sound Speeds and Pipe Size Data,
914-004), or use the Model DF868’s on-line
Help Menu
(see the
Programming Manual
for details).
For wetted transducers, skip to step 7.
2.6.5 Lining
6.
Press
[F1]
if the pipe does not have a
Lining
, or
[F2]
if it does have a lining. If you select
YES
, complete the steps
below.
a.
Use the
[F1]-[F4]
and [
keys to select the
Lining Material
. Options include Tar, Pyrex, Asbestos, Mortar,
Rubber, PTFE and Other. If you choose “Other,” the DF868 then asks you to enter the lining sound speed. If you
do not know the lining sound speed,
Sound Speeds and Pipe Size Data
(914-004)
lists some standard materials
and their corresponding sound speeds.
b.
Enter the known
Lining Thickness
, in the same units used for the pipe OD, and press
[ENT]
. Then proceed to step
9.
2.6.6 Path and Axial Length
7.
Enter the
Path Length
of the ultrasonic signal. Press
[F1]
or
[F2]
to select the desired units, and press
[ENT]
.
Note:
The factory has calculated both the transducer signal path length
(P)
and the transducer signal axial length
(L)
,
based on the exact transducer configuration used for the application. These values are engraved on the
flowcell and/or are included in the documentation supplied with the meter. See Appendix D for an explanation
as to how these values are calculated.
8.
The next prompt varies, depending on whether you selected Transit-Time or TransFlection in the
ACTIV
menu.
•
If you selected Transit-Time, the DF868 asks for the
Axial Length
. Enter the supplied value. Press
[F1]
or
[F2]
to
select the desired units, and press
[ENT]
.
•
If you have selected TransFlection, enter the number of degrees for the
Transducer Angle
, and press
[ENT]
. Skip to
step 10.
2.6.7 Tracking Windows
Note:
This step only appears if you have selected Transit-Time.
9.
Press
[F1]
if you do not want
Tracking Windows
, or
[F2]
if you want to enable the windows. (Tracking windows are
used to detect the receive signal when you are unsure of the fluid soundspeed.)
