DMM - Deflection Multi Meter

The measuring device, which consists of a level laser and DMM units, measures the deflection or settlement of a structure from several points in real time, which makes it unique compared to other measurement methods, such as a total station. The DMM measuring device is suitable, for example, for measuring the deflection of a bridge during test loading and can also be used for long-term monitoring of the structure. The resolution of the DMM receiver is 0.5 mm. The DMM receivers are all of the so-called ER (Extended Range) model, whose functionality has been tested to work at a distance of at least 350 meters from the Spectra Precision GL700 laser. There are two models in the series, the DMM ER160 and the DMM ER320, of which the measurement range in the vertical direction of the former is 160 mm and the latter is 320 mm.

The DMM units (sensors) are connected to each other in series and they are read by a computer via an RS-485 cable, which also supplies the operating voltage to the system. The data transfer uses the MODBUS protocol, which allows the DMM units to be connected to other measurement systems. The measurement results can be viewed with any measurement program that uses the MODBUS protocol. The operating voltage is 12 V DC and the voltage input is protected against overvoltages.

In many cases, the DMM units can also be attached to the structure with clamps or magnets, which makes the system very flexible and quick to install.

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