Safeline Signature Operating And Instruction Manual page 69

How to Manually Trim The Phase and/or
Sensitivity
The objective of the following procedure is to ensure
the setting of phase and sensitivity are optimised
following automatic setup.
The correct setting of the phase will be one value
which will give minimum signal from the product on
the bargraph display, this is known as the "null point"
setting. Changing the phase setting up or down in
value from this setting will increase the amplitude of
the signal.
The correct setting of the sensitivity will be a value
which gives a peak signal from the product of 3 to 4
bars on the LED bargraph display.
1) Pass the product through the aperture in its
normal manner to create a worst case product
effect signal, for more details refer to 'Notes On
Passing Product Through The Detector'.
2) If required adjust the sensitivity so that the peak
signal from the product gives 3 to 4 bars on the
LED bargraph display. Press the 'Enter' key to
store the new setting in memory.
3) Adjust the sensitivity so that the peak signal from
the product gives a reading on the LED bargraph
display of approximately half full scale (i.e. 10
green bars), refer to note 1).
4) To verify/optimise the "null point" set by the
automatic setup, increase the phase setting in
steps of 1° and at each step observe if the
amplitude of product signal indicated on the
bargraph display reduces. If an increase in
product signal is observed, then decrease the
phase setting in steps of 1° and at each step
observe if the amplitude of product signal
indicated on the bargraph display reduces.
For example if the automatic setup value is 90°,
and as the phase setting is increased there is a
clear reduction in signal as we change from 90° to
91°, and then from 91° to 92° the signal starts to
increase again, this indicates that the "null point"
is between 90° and 92°.
4618-021
OPERATING INSTRUCTIONS
5) Now reduce the phase setting in steps of 0.2° i.e.
91.8°, 91.6°, 91.4°, 91.2°, etc. until the product
effect signal is reduced to a minimum and then
just starts to increase again.
For example, if as the setting is reduced there is clear
reduction in signal from 90.8° to 90.6°, and then
from 90.6° to 90.4° the signal starts to increase
again, this indicates that the "null point" is
between 90.8° and 90.4°. Using the 0.1° digit
adjust the phase setting up and down until
minimum signal i.e. the "null point" is found.
6) Although not always necessary a more precise
"null point" will be found by now using the 0.01° in
a similar manner to the 0.1° digit as described in
5).
The phase control circuit is now aligned to the product
signal, next adjust the sensitivity so that the
product signal gives a maximum signal of 3 to 4
green bars on bargraph display, refer to Note.
7) Check the susceptibility of the detector to
vibration, if unacceptable (i.e. system vibration is
showing on the bargraph) reduce the sensitivity
until acceptable.
8) Press the 'Enter' key to store the new settings in
memory.
Note
When using the phase control to minimise product
signals the detector may become more susceptible to
vibration. The final setting of the sensitivity may be
limited by vibration effects rather than product effect.
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