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FCO770 Users Guide Issue 1
TEST DATA MENU
This menu is used to define the test pressure, fail levels, timings etc. for each test. Up to 300
different tests can be defined. When you enter the menu you may select the test to view/edit
from a list.
TEST SELECTED
•
Select the test number from the list of tests displayed. All the tests parameters will
then be available to alter.
TEST I/D
•
You may assign a descriptive text identification of up to 16 characters to each test.
TYPE
•
Define the type of test to perform.
•
Options:
o
LEAK
: Checks that components do not leak more than an acceptable level. The
test item is pressurised, and then isolated from the pressure source and allowed to
stabilise. Once stabilised a leak is indicated by a pressure loss. This pressure loss
is automatically converted to a flow reading if flow units are selected in the test
data menu.
o
BLOCKAGE
: Checks that components are not blocked more than an acceptable
level and do not have too great a leak. The test item is pressurised, and then
isolated from the pressure source. The level of flow is determined by checking the
test pressure after a pre-set time. If the pressure is above the FAIL HIGH level
then a blockage is indicated. If the pressure is below the FAIL LOW level a gross
leak failure is indicated. Set the FAIL LOW level to zero disable the gross leak
check. If the flow is too large to discriminate with this method it is possible to
continue filling during the test stage and perform a back-pressure test.
o
PERMFILL
: Permanent Fill is not really a test – it simply applies the pre-set
pressure to the test item until the instrument is reset. It can also be used in a
sequence of tests with continue on start.
o
RAMP
: In many areas of manufacture there is a need to measure the pressure at
which a device actuates, e.g. pneumatic cylinders, pneumatic valves, pressure
switches, pressure relief valves and oil seal fault pressures. An external needle
valve is used to generate a pressure ramp (rising or falling). At the point of
actuation the volume in the test item starts to increase which causes a change in
the rate of the pressure ramp. The ramp test detects this change and checks the
pressure against upper and lower limits. This test can also be used with pressure
switches where an external input is used to determine the actuation point.
o
DUMP
: This is a variation of the LEAK test for use with sealed items. A test jig
forms a chamber around the test piece. A reference volume is prefilled to a set
pressure. When the test is started the reference volume is disconnected from the
air supply and connected to the test chamber. The resulting pressure applied to the
test piece is checked to detect gross leaks, and then a differential pressure drop
leak test is made. Any variations of the prefill pressure may be compensated for,
giving a more sensitive gross leak check.
Содержание FCO770
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