EN
ar
bg
hr
cs
da
nl
fi
fr
de
el
hi
it
ko
no
pl
pt
ro
ru
es
sv
tl
iw
id
lv
lt
sr
sk
sl
uk
vi
et
hu
th
tr
fa
ms
hy
ka
ur
bn
mn
ta
kk
uz
ku
crack gauges
The JMDL-32XXAT Smart Single-Point Bedrock Displacement Meter extends Kingmach crack gauges into embedded rock and foundation monitoring. It is designed for tunnel rock mass deformation, dam bedrock deformation, slope sliding, and foundation pit face movement. The assembly includes a flange, electrical displacement sensor, tie rod, anchor head, and PVC pipe, forming a practical embedded instrument for single-depth displacement. Listed models include 50 mm, 100 mm, and 200 mm ranges, each with 0.01 mm resolution. Product information lists displacement accuracy of 0.5%FS, temperature accuracy of plus or minus 0.5 degrees Celsius, and an operating temperature range from -30 degrees Celsius to +80 degrees Celsius. This product is useful where the monitoring point needs to be anchored into a known layer rather than mounted only on a visible surface. In tunnels, dams, slopes, and deep excavations, that embedded layout helps link surface observations with movement inside the rock or foundation body. During project setup, the measuring point should be matched with the expected travel direction, available mounting space, cable route, and required acquisition interval. This prevents a short-range joint instrument from being used on a long-travel point, or an exposed sensor from being placed where an embedded anchor is needed. It also helps the monitoring team set a baseline that can be defended during acceptance and later maintenance review.
Application of crack gauges
In industrial automation and equipment monitoring, crack gauges are used for hydraulic cylinder stroke, machine tool positioning, gate movement, construction machinery displacement, and linear motion control. The site pain point is different from civil monitoring: readings must often be fast, absolute, repeatable, and resistant to wiring mistakes or mechanical wear. Kingmach JMCW-21XXADT magnetostrictive meters provide non-contact absolute displacement measurement over 0 to 1000 mm, 0.01 mm resolution, plus or minus 0.05%FS accuracy, RS485 communication, IP67 protection, average current below 60 mA, and reverse polarity protection up to -36V. For equipment with cable travel, JMLS-22XXADT wire rope sensors provide 500 mm, 1000 mm, and 2000 mm ranges with 0.2%FS accuracy and compact dimensions of 115 mm by 85 mm by 100 mm. These products help operators track position drift, stroke limits, gate opening, and machine movement in harsh workshops or outdoor installations. During operation, the monitoring team should keep the baseline, temperature, inspection notes, and nearby sensor behavior in the same review file. This makes it easier to tell whether a movement trend comes from normal service, a repair event, changing load, water influence, or developing structural risk. Clear records also help owners decide when a field inspection is needed instead of waiting for visible damage.
The future of crack gauges
The future of crack gauges will be shaped by connected monitoring rather than isolated field readings. Kingmach products already include digital detection, RS485 communication on selected models, built-in memory, stored calibration data, and compatibility with automatic acquisition systems. The next practical step is cleaner connection between the sensor identity, the monitoring point, and the platform curve. A displacement value should arrive with its model, serial number, range, calibration coefficient, zero value, temperature, and installation position. That will reduce channel errors and make later review faster. In bridges, tunnels, dams, slopes, and foundation pits, future systems will compare displacement with strain, load, tilt, settlement, rainfall, water level, and construction events. Warnings will depend less on a single limit and more on the pattern of movement across several related sensors. The strongest systems will still depend on careful installation, because digital tools cannot correct a loose bracket, wrong range, or poorly recorded baseline. Clear reporting will make displacement monitoring more useful for non-specialist decision makers while preserving the detail engineers need.
Care & Maintenance of crack gauges
For flexible geogrid crack gauges, installation care is more important than later access because the product may be buried inside reinforced soil. Kingmach JMDL-24XXAT uses a bendable measuring rod, 30 mm and 50 mm ranges, 0.01 mm sensitivity, 0.5%FS accuracy, 20-point curve fitting, and a designed service life up to 30 years. Both ends of the geogrid should be clamped with the flexible sensor sections using mounting brackets so deformation transfers reliably. Avoid sharp bending, cable tension, bracket slippage, and damage during filling or compaction. Record the geogrid layer, chainage, depth, sensor direction, zero value, and backfill date. During operation, compare displacement with settlement and rainfall records. If the trend changes after heavy rain, traffic loading, or nearby excavation, inspect accessible cabinets and cables before deciding whether the buried geogrid movement itself has changed. Keep the installation photo, point number, zero value, and expected movement direction with the commissioning record for later review. If a reading changes after maintenance work, inspect the base, anchor, cable, and cabinet before assuming the structure itself has moved.
Kingmach crack gauges
crack gauges are especially useful when the movement path is known but the rate and timing are uncertain. Kingmach's differential displacement meter uses two coupled inductive coils so equal and opposite magnetic flux changes can reduce environmental interference and thermal drift. The magnetostrictive JMCW-21XXADT provides non-contact absolute displacement measurement over 0 to 1000 mm, with 0.01 mm resolution, plus RS485 communication and IP67 protection. The wire rope JMLS-22XXADT converts cable extension into digital data for long or curved movement paths. These different mechanisms let designers match the sensor to the physical path instead of forcing one format into every project. A short expansion joint, a hydraulic cylinder, a landslide monitoring line, and a tunnel clearance point may all be called displacement, but each one needs its own mounting, range, and data plan. The point should be named on the drawing, linked with its cable route, and checked against the expected movement direction before the first automatic reading is accepted. For daily review, the reading should be compared with nearby points, recent weather, site operations, and any loading event that could explain the movement.
FAQ
Q: What are crack gauges used for?
A: They measure movement such as relative displacement, crack width, expansion joint travel, bedrock deformation, rock layer movement, geogrid deformation, formwork settlement, and equipment stroke.
Q: Which Kingmach models belong to this category?
A: Common models include JMDL-21XXAT, JMDL-22XXAT, JMDL-24XXAT, JMDL-31XXAT, JMDL-32XXAT, JMDL-49XXAT, JMDL-52XXADT, JMCW-21XXADT, and JMLS-22XXADT.
Q: What range should be selected first?
A: Start from the expected movement. Short joint monitoring may need 20 mm to 100 mm, while draw-wire or equipment travel may require 500 mm to 2000 mm.
Q: Can these products support remote monitoring?
A: Yes. Several Kingmach models support digital transmission, RS485 communication, automatic acquisition, integrated testers, or unattended monitoring systems.
Q: Why is the baseline reading important?
A: All later movement is compared against the starting point. The baseline should be recorded after the sensor, bracket, anchor, cable, and structure are stable.
Reviews
Christopher Martinez
Very satisfied with the readouts & data loggers. User-friendly interface and supports multiple sensor inputs.
Matthew Garcia
Instrumentation cables are durable and perform well even in harsh environments. Will definitely order again.
Latest Inquiries
To protect the privacy of our buyers, only public service email domains like Gmail, Yahoo, and MSN will be displayed. Additionally, only a limited portion of the inquiry content will be shown.
Evelyn***@gmail.comSouth Africa
Hi, we are a contractor working on tunnel construction and need settlement sensors and displacement ...
Isabella***@gmail.comGermany
Hello, we are evaluating weir flow meters for a water management project. Please share accuracy deta...