Hardy HI 1756-nDF - Manual (Page 56)

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Chapter 6
B1 - Guidelines for Instabilities on Formerly Operating Systems
(Cont’d)
OK?
Yes
No
B1
OK?
Yes
No
Vessel -
When inspecting a vessel, the Center of Gravity (COG) should be
low and centered equally over all the load cells. Insure the load is
directly over or under the load point to avoid side-loading and
that there isn’t any side loading from piping or external forces.
Install flexures on all piping to insure a free floating vessel.
Make sure the vessel and load cell mounts are mechanically stable
and fixed.
Large changes in individual load cells indicate a shift in the COG or
faulty load cells.
Piping and motors can effect the individual load cell readings.
Allow for a higher reading on load cells that support motors and
piping.
Insure pneumatic lines are not applying pressure to the vessel
when energized.
Use check (stay) rods to minimize vessel movement.
Make sure the check rods are loose and not interacting with
the vessel.
Power down all vibration, vacuum and pressurization equipment
during the test process.
Configuration Settings
Incorrect WAVERSAVER settings can cause unstable weight readings.
Adjust to the lowest WS setting that gives you a stable reading.
Higher frequencies with low amplitude vibrations - Use WS settings 1
or 2 lower frequencies with high amplitude vibrations - Use WS setting
3 or higher incorrect number of decimal places. Reading weight
increments beyond the equipment applications level. (Sed Guideline
Calculations below)
Repeatability -
Divide the total load cell capacity, including decimal points by 10,000.
(Expected stable weight reading)
Resolution -
Divide the total load cell capacity, including decimals points by 30,000.
(The amount you can expect to see but not necessarily stable
C
Return to
A
STABILITY
B2
B3