FCO770 Users Guide Issue 1
Page 45
PREFILL TIME
•
Only displayed if enabled in the Global Settings menu
•
For standard prefill
, this sets the time that the prefill regulator signal is enabled
before the fill pressure is set. The signal is turned off at the end of the prefill time. The
prefill regulator signal may be used to select an alternative pressure regulator. When
set to zero, the prefill function is disabled.
•
For auto prefill
, this is a limit that should be set to the maximum allowable time to
prefill. Prefill will end when the prefill pressure is reached or when the prefill time
expires if the pressure is not reached. Set to zero to disable the time limit.
VENT PREFILL TIME
•
Only displayed if enabled in the Global Settings menu
•
If standard prefill was used then the test piece may be vented before the applying the
fill pressure. Set to zero if you do not want to vent the prefill pressure.
•
This is not used with auto prefill.
FILL TIME
•
Sets the time that the test pressure is applied for before the fill valve is closed and the
stabilisation timer is started. This time should be sufficient to allow the component to
be filled to the required pressure. Typically you should adjust the fill time to about
30% more than the time taken to fill to the required pressure.
STAB. TIME
•
Sets the time that the test item is allowed to stabilise for after the fill pressure has
been removed before the leak test is started. With a known good test item and starting
each test cycle with the item vented, set the stabilisation time to the shortest that will
give a PASS result with either zero reading or a small repeatable reading.
TEST TIME
•
Set the required test time. For pressure drop leak units the test time determines the
leak fail level, e.g. 5 Pa in 3 seconds. For flow leak units the test time should be set to
give a stable reading, typically 2-4 seconds. Note that long test times can lead to the
transducer exceeding its range and a fail will be given.
VENT TIME
•
The vent time should be set if an external vent valve is fitted to the system. The time
must be long enough to allow the pressure in the test item to decay to a safe level to
ensure that the test item is not unclamped while pressurised.
TEST VOLUME
•
Only displayed when flow units are selected in the Global Settings menu.
•
The FCO770’s leak test measures differential pressure. In order to display the leak
correctly in flow units, e.g. cc/min, the instrument needs to know the volume of the
test item in cc. The maximum volume is 99.9999 litres.
OFFSET
•
This value is deducted from any leak readings.
Summary of Contents for FCO770
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