ONLINE ELECTRONICS LTD
ID5000A_5001_A03
Page 17 of 21
4.3.
PARAMETER SETUP
Every time the unit is installed on a pipeline this setup procedure should be followed. For the
following example let’s assume we know the external diameter of the pipe is 24” so we should
expect to see a detected diameter of around 61cm.
1.
With the unit mounted on the pipeline switch to SETUP
MODE 1. We see the screen to the left. Notice the strong
transmit pulse and a weak reflection at 60cm
–
we know
we are working on a 60cm diameter pipe. The signal is
too weak as it does not cross the threshold level (middle,
horizontal line) so the diameter is not being detected.
We will increase gain until it is well over this level.
2.
After increasing gain, notice that when the signal crosses
the threshold level (middle, horizontal line) the correct
diameter is detected. It would be enough to leave the
unit as it is now however there are some spurious signals
immediately before the main reflection which cross the
maximum noise level (bottom horizontal line). We may
be able to reduce these by varying the pulse width.
3.
After varying the pulse width we have found the position
at which the reflected signal is proportionally largest
compared to the spurious signals before it. However, the
overall signal strength has reduced to below the
minimum signal level (top horizontal line) so we need to
turn up gain again.
4.
After increasing the gain notice we now have a good
strong signal well above the threshold level (middle
horizontal line), the maximum signal level is above the
minimum signal level and the spurious signals are well
below the maximum noise level. Also we can see the
detected diameter reflects the position of the first
reflection along the ruler. It may be necessary to
readjust gain and pulse width a few times to iteratively
reach these optimum settings.
5.
Once the optimum settings have been determined select SAVE GAIN AND PW from the
display menu to save the settings. If this step is omitted then the settings will be lost next
time the mode is changed or the unit is switched off.
6.
Set DETECT COUNT as per section 3.3.11 SET DETECT COUNT.
7.
Set INDICATOR DELAY as per section 3.3.12 SET INDICATOR DELAY.
8.
Set MINIMUM DIAMETER as per section 3.3.13 SET MINIMUM DIAMETER.
9.
Return to DETECTION MODE 0 and ensure that after the DETECTING DIAMETE
R… message
the correct pipe diameter is displayed and that the signal quality is over 95%. The unit will
then start waiting for a pig passage. If this is not the case re-enter SET UP MODE 1 and
adjust settings as necessary.