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JM Series Vibrating Wire Jointmeter

RUGGED DISPLACEMENT SENSOR

HIGH ACCURACY AND RESOLUTION

WATERPROOF UP TO 5 MPA

The JM series of vibrating wire (VW) displacement transducers are used to measure movements at joints and cracks in structures and foundations (concrete, rock, soil)

Description

The JM utilizes a vibrating wire sensor attached to a spring tensioned between two anchors. Any variation of distance between these anchors will change the tension in the wire. The sensor is protected by a sliding stainless steel housing.

 3 models are available: 

The JM-S Crackmeter is attached to the surface of the structure using groutable or bolt-on anchors. Ball joints at each end of the sensor compensate for any anchor misalignment. The JM-S is also available in 3-D configuration for measurement in three orthogonal directions, or with special clamps for installation on a geogrid. 

The JM-E Embedment Jointmeter is embedded in concrete structures such that its active length spans the construction joint to be monitored. This model consists of two sections: the socket and the sensor, which are installed and connected during two successive concrete lifts. 

The JM-T is used in Borehole Extensometers. 

A thermistor is integrated to the JM allowing temperature measurement.

Specifications

Range

25, 50, 100, 150, 2001, 2501, 3001 mm

Overrange

1.00 × range

Accuracy

± 0.25 % F.S. (± 0.1 % in option)

Resolution

0.02 % F.S. (min.)

Operating temperature

−20 °C to +80 °C

Thermistor

3 kΩ

Cable

IRC-41A, IRC-41AP, IRC-3902, IRC-21A (JM-T)

Length ‘A’ of JM-S (mid-range)

289.5, 357, 500, 651, 797, 933, 1076 mm

Length ‘A’ of JM-T (mid-range)

230.5, 298, 442, 593, 738, 875, 1018 mm

Length of JM-E (at rest)

383, 432, 602, 772 mm

Diametre of JM-E (flanges)

47.6 mm

 Ranges not available for JM-E model
2 Available only with JM-E
Ordering Info

Please specify:

  • Model
  • Cable length and type
 

Optional accessories:

  • Mounting accessories: Universal joints, anchor types (groutable rebar or expandable)
  • Other special mounting accessories
  • Readout instruments
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