Install pipes and lines with minimal effort
Trenchless pipe and cable installation enables modern infrastructure projects without tearing up roads or disrupting the landscape. This reduces emissions, noise, construction time, and traffic disruptions—while maintaining high efficiency.
For these highly automated systems to operate reliably, precise and robust sensor technology is essential. A prime example of this is Novotechnik’s RSM-2800 series of multiturn sensors, which perform critical functions in TRACTO’s HDD units.
Why HDD drilling rigs require precise sensors
In the horizontal directional drilling method, the steerable drill head first creates a pilot bore along the planned route. As the drill string is withdrawn, the borehole is then enlarged using an reamer before the pipe is pulled in. A flushing fluid consisting of water and bentonite aids in material removal and stabilizes the borehole.
To ensure that the process runs automatically, the boom crane and feed carriage must be positioned precisely. The boom gripper retrieves three-meter-long drill rods from the magazine, moves them vertically and horizontally, and inserts them precisely into the feed system. Accuracy, repeatability, and robust operational reliability are critical here.
Previous models used 10-position potentiometers for this purpose—a solution that is now being replaced due to wear and maintenance requirements. The alternative: contactless, wear-free multiturn sensors.
The solution: Multiturn sensors with GRM technology
The RSM-2800 series of magnetic multiturn sensors operate on the basis of the GMR (Giant Magnetoresistance) effect. They measure revolutions in absolute terms, without contact, and even retain this data when power is off.
Key technical features
- Records up to 16 revolutions without an external power source
- True Power-On Technology: Position values are retained even after the power is turned off
- Resolution up to 16 bits (analog) or 18 bits (digital, SSI/SPI)
- Measurement at rotational speeds up to 800 rpm
- Linearity deviation less than 0.05% (over 10 revolutions)
Used in boom cranes and feed carriages
TRACTO is using multiple RSM-2800 sensors in its new generation of flush drilling rigs, the Grundodrill JCS/ACS130:
Vertical and horizontal axes of the jib crane
- Two sensors detect and record up to 9 revolutions
- Communication via 4–20 mA current output
- Precise positioning for loading and unloading the drill rods
Position detection on the feed slide
- Another multiturn sensor monitors 10 revolutions
- This covers the entire 3.5-meter travel range
- Ensures that the drill rods are reliably inserted into the borehole and extended
The RSM-2800 is specifically designed for harsh environmental conditions:
- IP67 rating
- vibration- and shock-resistant
- temperature-resistant plastic housing
- Backlash-free plug-in coupling for easy installation
- pre-assembled M12 connector
- Fully integrated, shielded connection cable
- Compact design with a diameter of 28 mm
Even special installation scenarios, such as on the crane’s vertical axis, can be accommodated through practical adaptations to the mounting solution—a result of the close collaboration between Novotechnik and TRACTO.
Technology Explained: The GMR Effect
The multiturn sensor uses a micromagnetic layered structure consisting of magnetic and non-magnetic thin layers. Their electrical resistance changes depending on the orientation of the magnetic layers. This difference is used to:
- Accurately measuring revolutions
- Save position values permanently
- to provide absolute values even when the power is off
The output is provided, for example, as an SSI signal; versions with SPI or analog outputs are also available.
