HLS%20Monitoring%20System%20Georg%20Gassner,%20SLAC%20/%20MET%20October%2021,%202005 - PowerPoint PPT Presentation
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HLS%20Monitoring%20System%20Georg%20Gassner,%20SLAC%20/%20MET%20October%2021,%202005
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The proposed Hydrostatic Level Systems (HLS) has several significant ... 2 inch stainless steel pipes to connect the pots for optimal. damping and maintenance ... – PowerPoint PPT presentation
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Title: HLS%20Monitoring%20System%20Georg%20Gassner,%20SLAC%20/%20MET%20October%2021,%202005
1
HLS Monitoring System Georg Gassner, SLAC /
METOctober 21, 2005
- HLS Introduction
- HLS Principle
- Types of Sensors
- Integration of HLS with the Undulator
2
Hydrostatic Leveling System Introduction
- The free surfaces of bodies of water have been
used for several thousand years as a vertical
reference. - The proposed Hydrostatic Level Systems (HLS) has
several significant advantages over optical
methods in determining height differences between
two points. Some of these advantages are - No direct line of sight needs to exist
- Not affected by optical refraction
- Higher accuracy
- Fully automated
- Self calibrating
- Equipotential surface is the reference
3
Motion of Earth Surface
- The disadvantage of using the equipotential
surface as a reference is that the earth surface
itself is not stable but in constant motion. - Earth tides due to sun
- and moon
- Are up to 30mm
- for a 123 m long
- Undulator
- Can be modeled
- Ocean tide loading
- and atmospheric loading
- Can reach up to 30 mm
- Can not be modeled
4
HLS Principle
Hydrostatic Leveling Systems are based on the
principle of communicating vessels or more
precisely on the equilibrium of the pressure of
the fluid in the communicating vessels. This is
mathematically described by the Bernoulli
equation. p r g Z const. Dp 0.10 hPa
gt DZ 1.02 mm DTemp 1C Z 100 mm gt
DZ 67 mm
5
HLS Configuration
- There are two principle configurations
- Full filled pipe system
- Faster damping time lt2 min
- Easier installation
- Half filled pipe system
- Temperature differences
- do not affect the measurements
- Damping time 10 min
6
Types of Sensors - Capacitive Sensor
- Principle
- Measures the Capacity C of the System
- Attributes
- Proven to work for many years
- Inexpensive
- Precision lt 1 mm
- Accuracy (10 mm range) lt 5 mm
- Possibly affected by drift
- Absolute height measurements are only indirectly
achievable
7
Types of Sensors - Ultrasound Sensor
- Principle
- Measures the runtime of an
- ultrasound pulse
- Attributes
- No drift (self calibrating)
- Precision lt 0.1 mm
- Accuracy (10 mm range) lt 3 mm
- Absolute Measurements
- More expensive
- No long-term experience (10 years)
8
HLS measurements related to the Girder
- Any three HLS sensors provide independent
monitoring of - Height of the girder
- Roll of the girder
- Pitch of the girder
- The fourth sensor provides a controlled
measurement
9
Integration of HLS with the Undulator
- Three capacitive sensors per girder
- reliable determination of height, roll and pitch
- One ultrasonic sensor per girder
- Absolute measurements
- Calibration of the system
- Controlled measurements
- 2 inch stainless steel pipes to connect the pots
for optimal - damping and maintenance
- All sensors are connected with TCP/IP (IEEE
802.3af) - Following a standard (off the shelf products)
- Power supply included
- Each sensor communicates independently from all
others
10
Conclusion
- Reliable and controlled method for monitoring
- heights of the girders (1 mm level small range)
- pitches of the girders (0.5 mrad)
- rolls of the girders (2 mrad)
- Damping within 10 min
- Supplies Wire Positioning System with information
to determine the sag
11
End of Presentation
