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 meters
Kingmach crack meters include the JMDL-31XXAT Smart Multipoint Displacement Meter for tunnels, rock slopes, foundation pits, and surrounding rock layers. The product uses displacement gauges, PVC measuring rod protective tubes, anchor heads, and multipoint installation kits that support three to five monitoring points. Installation is performed by drilling and grouting, with anchor heads fixed at different depths so each layer can be observed separately. Listed models include 50 mm, 100 mm, and 200 mm ranges, all with 0.01 mm resolution. The sensing principle uses an LC oscillation circuit: as the measuring rod moves inside the coil, magnetic reluctance and inductance change, causing the output frequency to change in a linear relationship with displacement. Because the rod and coil work without contact, the structure is less vulnerable to mechanical damage during installation. The built-in memory stores model, serial number, calibration coefficients, and up to 600 measurement records for later traceability. 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 meters
In dam and hydropower projects, crack meters can track joint opening, bedrock deformation, gate position, dam body movement, tunnel portal movement, and displacement between monitoring points. The pain point is long service life under water level fluctuation, seepage, temperature change, and difficult access. Kingmach JMDL-32XXAT single-point bedrock meters are designed for dam bedrock deformation and provide 50 mm, 100 mm, and 200 mm ranges with 0.01 mm resolution. JMDL-52XXADT differential meters can monitor relative movement in concrete joints with RS485 digital output and plus or minus 0.1%FS accuracy. JMCW-21XXADT magnetostrictive meters provide 0 to 1000 mm absolute position measurement for gates, equipment stroke, or structural movement. JMLS-22XXADT wire rope sensors support up to 2000 mm for larger displacement paths. Combined with water level, seepage, strain, and temperature monitoring, displacement data helps dam managers understand deformation behavior across operating cycles. 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 meters
Wireless and low-power networks will change how crack meters are deployed on difficult sites. Many displacement points are located on slopes, dam shoulders, tunnel portals, remote rail subgrades, or temporary construction zones where cabling is expensive and easy to damage. Kingmach displacement products already support automatic acquisition in several forms, and future field layouts can combine wired RS485 points, LoRa or 4G gateways, solar power, and compact edge devices. The engineering task will be to preserve reliable baselines while reducing field maintenance. Sensors with built-in memory and stored calibration data help because the point can retain key identity information even when a gateway is replaced. Remote power planning, connector sealing, lightning protection, and clear channel naming will become as important as the sensor range itself. For remote terrain, the biggest gain will be fewer unnecessary site visits: teams can review battery status, data gaps, and movement direction before sending technicians into a hazardous or hard-to-access location.
Care & Maintenance of crack meters
For crack meters installed at cracks, joints, and expansion joints, maintenance should focus on bracket stability, rod alignment, cable protection, and baseline traceability. Kingmach JMDL-22XXAT crack gauges may use different measuring rods and universal bases, so the mounting points must remain firm while the structure moves naturally. Avoid placing rods where they can be hit by workers, tools, vehicles, concrete debris, or repair materials. During inspections, check whether the crack edge has spalled, whether the base has loosened, whether water has entered the connector, and whether the displayed movement agrees with nearby observations. Because the product can store up to 600 measurement results, compare field readings with stored records before resetting values. If temperature versions are used, keep temperature data with displacement data so seasonal opening and structural movement are not confused. 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 meters
crack meters are used when a structure needs movement data that can be reviewed, compared, and acted on before deformation becomes visible. Kingmach covers short range crack movement, expansion joint travel, rock layer displacement, geogrid deformation, draw-wire movement, and long stroke position tracking. The category includes JMDL-21XXAT general-purpose displacement meters, JMDL-22XXAT crack gauges, JMDL-24XXAT flexible meters, JMDL-31XXAT multipoint meters, JMDL-32XXAT bedrock meters, JMDL-49XXAT formwork meters, JMDL-52XXADT differential meters, JMCW-21XXADT magnetostrictive meters, and JMLS-22XXADT wire rope sensors. On site, this means one product group can cover bridge joints, tunnel portals, slope movement, dam deformation, railway subgrade settlement, and industrial linear motion. The value is not only the displayed millimeter reading. It is the ability to connect movement, time, temperature, construction activity, and warning limits into one record. 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: Which crack meters fit crack monitoring?
A: The JMDL-22XXAT Smart Crack Gauge is designed for cracks, joints, and expansion joints in bridges, buildings, roads, railways, dams, tunnels, and slopes.
Q: What ranges does the crack gauge list?
A: Listed models include 20 mm, 50 mm, 100 mm, and 200 mm ranges, with 0.01 mm resolution on the 20 mm to 100 mm versions and 0.05 mm on the 200 mm version.
Q: How many records can the crack gauge store?
A: Product information states that it can save up to 600 measurement results, including time, temperature for temperature versions, displacement values, and zero-point value.
Q: What installation details matter most?
A: Base stability, rod alignment, connector sealing, cable protection, and a clear zero reading matter more than a polished-looking installation.
Q: Can it be used for long-term observation?
A: Yes. The product is described for long-term monitoring, especially where crack width changes need stable and repeatable measurement.
Reviews
David Wilson
We purchased displacement transducers and settlement sensors, and the quality exceeded our expectations. Easy installation and reliable performance.
Michael Anderson
The strain gauges and load cells are extremely accurate and stable. They performed very well in our bridge monitoring project. Highly recommended!
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.
Emma***@gmail.comCanada
Dear Sir/Madam, we are interested in displacement transducers and settlement sensors for a geotechni...
Charlotte***@gmail.comUnited Arab Emirates
Hi, we require instrumentation cables suitable for harsh environments. Could you advise on specifica...