A String Pot or Draw Wire sensor are sensors used for vertical displacement material compression and creep monitoring.
The sensors are typically packaged in a NEMA rated enclosure with an extended wire attached to it allowing it to span from floor to floor in a building. Depending on the expected travel, different models are available. The compact size, wide variety of travel ranges and favorable price as compared to LVDTs make this sensor attractive in a variety of different applications. See ASTM publication Volume 41, Issue 4 (July 2013) titled Monitoring of Vertical Movement in Four-Story Wood-Frame Building in Coastal British Columbia for detailed information on how String Pots can be used to monitor vertical displacement and compression of buildings.
String Pot Sensor
- 50mm Measuring Range used for floor to floor compression
- 250mm Measuring Range used for full building and large scale monitoring
- Compatible with SMT WiDAQ and A3/A2 Dataloggers
- Mounted in NEMA rated enclosure with ½” conduit interface
- Draw wire extensions available up to 300 feet
- Different terminations and hook boxes are available depending on the mounting requirements
Specifications SPOT-00-50mm
Measuring Range: 50mm
Linearity (conductive plastic pot): ±0.5% FSO
Resolution (with A3/WiDAQ): 0.1mm
Specifications SPOT-00-250mm
Measuring Range: 250mm
Linearity (wire pot:) ±0.25% FSO
Resolution (with A3/WiDAQ): 0.1mm
Environmental
Operating Temperature: -20° to 80°C
Mechanical
Material: Housing: Plastic. Draw wire: stainless steel
Wire Mounting: Eyelet
Housing: NEMA rated enclosure with grommet for analog wire.
Wire Acceleration: ~5g
Wire Retraction Force (min): ~1N
Wire Extension Force (max): ~2.5N