Sensors for NIVELTRONIC Plus®, the VÖGELE System for Automated Grade and Slope Control.
VÖGELE set the benchmark when it comes to grade and slope control. The broad spectrum of different sensors offered for NIVELTRONIC Plus®, the VÖGELE System for Automatic Grade and Slope Control, ensures that the right sensor is available for every paving application. After reporting on non-contacting acoustic sensors, this second article will cover the range of mechanical VÖGELE sensors.
The Advantages of NIVELTRONIC Plus® at a Glance
- Unique: Automated grade & slope control system supplied directly by the paver manufacturer. Machine technology and grade & slope control are perfectly matched, thus ensuring an equally perfect pavement result.
- Wiring and connections are integrated into tractor unit and screed.
- Wide and varied selection of sensors permits use of NIVELTRONIC Plus® in all fields of applications.
- Automatic recognition of sensors connected for easy and quick set-up.
- Particularly easy, user-friendly control and monitoring of all NIVELTRONIC Plus® functions.
- Logical, self-explanatory symbols neutral in language support quick learning of all functions.
- NIVELTRONIC Plus®, fully integrated into the paver’s control system, does not require any extra training.
The range of mechanical VÖGELE sensors includes the Variable Mechanical Grade Sensor and the Slope Sensor. These sensors have direct contact with their references. Changes in the position of the sensors or the screed are registered mechanically while tracking the reference and converted into electrical signals. These signals are sent to the NIVELTRONIC Plus® System for Automatic Grade and Slope Control and a correction is initiated.
Visible measurement, robust technology
The key advantage of mechanical sensors is that they are insusceptible to external influences such as water, wind, sunlight, temperature fluctuations or air turbulence caused by passing traffic. Another advantage is that the actual measurement is "visible". This makes it particularly easy to check that the sensor has "stable" contact with the reference. The point at which the reference is tracked thus becomes instantly recognizable.
1. Variable Mechanical Grade Sensor
The Variable Mechanical Grade Sensor developed by VÖGELE combines the advantages of a sonic grade sensor with the high degree of precision typical of mechanical sensors. The underlying principle is simple: when tracking a reference, the upwards and downwards movements of the ski or bow are transmitted to the sensor. If there are any deviations from the desired value, the position of the screed is corrected automatically by NIVELTRONIC Plus®, the System for Automatic Grade and Slope Control.
Large measuring range of +/- 10cm
The Variable Mechanical Grade Sensor’s measuring range of +/- 10cm is very large for mechanical sensors. Indeed, it is comparable to that of a sonic sensor. The Variable Mechanical Grade Sensor is also configured at the touch of a button, just like the VÖGELE sonic sensors. It is recognized automatically by NIVELTRONIC Plus® when connected to the ErgoPlus® screed console. A simple touch of a button and it is zeroed and ready for use.
Versatile options for combination
The Variable Mechanical Grade Sensor offered by VÖGELE can be combined in many ways. It can be equipped with skis of 0.3m, 1m or 2m. The 30cm ski is especially suited to surfacing roadways with tight bends or roundabouts, as it does not impede the manœuvrability of the paver. When using the short ski, the reference is copied 1:1, with no levelling out of irregularities. If smaller irregularities in the reference are to be levelled out, the use of the 1m or 2m ski is recommended. In the event of longer irregularities, the combination with the 7m averaging beam is useful.
Use of the 7m averaging beam
Particularly long undulations in the base can be levelled out very well by combining the Variable Mechanical Grade Sensor with a 7m averaging beam and using a bow for referencing. The averaging beam is the right choice primarily on long job site stretches with no tight bends.
Highly accurate paving with tensioned wire
In order to achieve highly accurate paving along a tensioned wire, the Variable Mechanical Grade Sensor is ideal, too. It then combines with a bow. Tracking a tensioned wire is a method primarily used where no suitable reference is available, or in cases where the client expressly requests it. Extremely precise paving results can be achieved using a combination of tensioned wire and Variable Mechanical Grade Sensor, as the sonsor features a high degree of measuring accuracy allowing tolerances of no more than +/- 0.5mm.
2. Slope Sensor
No matter if the focus is on high horizontal surface accuracy or a pavement with an elevation on one side needs to be built – the Slope Sensor precisely picks up the actual crossfall and provides for highly accurate paving.
Measuring accuracy of +/- 0.05%
The transverse slope of the screed is measured with a fluid-filled Slope Sensor similar to a spirit level. Thanks to its high resolution, the Slope Sensor guarantees a high level of accuracy and is capable of picking up transverse slope across a wide range of +/- 10%. The crossbeam on which the Slope Sensor is fitted features a vibration-proof design, thus ensuring precise measurements under all job site conditions. The sensor stands out through a high measuring accuracy of +/- 0.05%, allowing a tolerance of no more than 0.5mm over a width of 1m. The position of the screed serves as a reference.
Combination with a grade sensor
There is no problem using the Slope Sensor in combination with any VÖGELE grade sensor up to a maximum pave width of 6.5 metres. The elevation measured on one side of the screed, and the transverse slope picked up on the other side, provide for a consistent paving result, true to line and level, across the full pave width.
Combining two grade sensors with the Slope Sensor
Two grade sensors plus the Slope Sensor can be connected simultaneously to VÖGELE NIVELTRONIC Plus®, although only two sensors are necessary for accurate grade and slope control. While paving, users can combine the Slope Sensor with either of the connected grade sensors, left or right, by simply switching over. There is no need for conversion or tedious plugging and unplugging. This opens up a variety of options for tracking available references. By the way: if grade sensors are used on the left and right sides, the current transverse slope is still displayed automatically on the ErgoPlus® screed console, without the slope sensor being used for grade and slope control.