Teledyne 4250, Installation And Operation Manual, Page: 72 / 204

4250 Flow Meter
Section 2 Programming
2-44
Figure 2-4 Measuring Level in Round Pipes
You should remove the sensor and mounting ring to measure the
level if either of the following occur:
• If it is not possible to measure the level upstream when
the sensor is installed (cramped quarters inside smaller
pipes).
• If the sensor and its mounting ring create a visible
“jump” in the stream.
This “jump” would be any noticeable disturbance on the surface
of the flow stream where it passes over the sensor and mounting
ring, and is typical of lower flows. See Section 3.6 for more infor-
mation. Enter this value with the number keys. LEVEL ADJUST
must be done
at the job site , while most other programming can
be done in the shop. Unless you have reliable information about
the size of the channel, you should measure that, also.
Note
It is very important to enter accurate measurements for both
the level in the stream and the dimension(s) of the channel, as
all calculations of flow will be based on these measurements. If
the values entered are incorrect, even by relatively small
amounts, all subsequent flow calculations will also be incor-
rect. For example, an error of only
1
•
4
" for a 3" level and
1
•
4
" for a
10" diameter round pipe can result in a combined error of over
14%!
Errors in level measurement have a greater effect on flow cal-
culations at low liquid levels. Dimensional errors tend to be
more significant at higher levels.
If you select pH for Parameter to Adjust, the following display
will appear. (pH will not appear as an option unless you have
selected it in
step 1 .) If you want to measure pH and pH does not
appear in this step, you must go back to step 1 and select pH
instead of NOT MEASURED.
You can perform a two- or three-point calibration for pH with the
pH sensor. Select the calibration that best suits your stream’s
profile. If the pH in your stream in generally below 7, you would
D
d
h
D – d = h (level)
This picture shows you how
to measure level. You then
enter this value with the
number keys. Note that
LEVEL ADJUST
must be
done at the job site , while
most other programming
can be done in the shop.
pH CALIBRATION
• pH 4 & 7 • • pH 7 & 10 • • pH 4, 7, & 10 •