Electro-hydraulic servo systems:
hydraulic positioning and servo
cylinders for precision-critical machinery
When a production line lives or dies by where an axis stops, to the millimetre, thousands of times a shift, ordinary hydraulics aren't enough. BLH Nobel designs, builds and maintains complete electro-hydraulic servo systems that turn raw hydraulic power into repeatable, controllable motion.
Our hydraulic positioning systems combine servo cylinders, servo valves, position sensors and pre-configured electronics into one engineered package, so you get the force of hydraulics with the accuracy and predictability of closed-loop control. For plant managers and OEM engineers, that means tighter tolerances, faster cycles, less scrap and far less unplanned downtime, backed by decades of control-and-regulation experience and thousands of axes already running across more than 100 countries.
What sets BLH Nobel apart
Servo cylinders with built-in feedback
Our POS 50 and POS 100 series hydraulic servo cylinders build an LVDT sensor straight into the cylinder body, removing exposed feedback hardware and shrinking the installed footprint.
Servo valves matched to the axis
The 650 and DDV 633/634 servo valve families cover roughly 10 to 80 l/min and 20 to 100 l/min, so flow is sized to the load rather than the other way around.
A complete servo positioning unit
The MicroPOS-4 servo positioning unit handles fast, accurate moves for both light and heavy machine shafts, with controlled acceleration and speed that minimise mechanical stress.
Clean, isolated feedback
The LVD 3 signal conditioner amplifies two LVDT channels with galvanic isolation between channels and supply, giving stable readings even in electrically noisy plants.
Digital fieldbus electronics
Fast two-way data transfer, straightforward commissioning and a genuine force and pressure control system, not position alone.
Delivered ready to run
Systems arrive pre-assembled in enclosures, cutting installation time and integration risk.
The products in every BLH Nobel servo system
Standard building blocks, combined and pre-configured to your axis. Each links through to the hydraulics catalog.
The closed loop, step by step
Command
A controller takes the target position for the axis as its set point.
Compare
It checks the commanded position against the actual position from the cylinder's sensor and calculates the error.
Meter flow
It drives a servo valve to meter precisely the right amount of hydraulic flow to the electro-hydraulic actuator.
Feed back & hold
The position transducer reports the real location continuously; the axis settles on target and holds it under load.
Because the loop runs hundreds of times a second, the system delivers true precision motion control: high thrust from hydraulics, governed by the responsiveness of digital servo electronics.
The difference is feedback and control
An on/off muscle
Extends or retracts until a stop, limit switch or operator tells it to halt. It has no idea where it is along its stroke. Motion is essentially on/off, with no profiling and no repeatable mid-stroke targets.
A programmable motion element
Carries an integrated linear displacement transducer, so it knows its exact position at all times and stops at any point on demand. Suited to hydraulic position control, smooth profiling and accurate force or pressure regulation.
Precision positioning for sawmill machinery
Sawmills are where this technology earns its keep. A dedicated sawmill positioning system is one of BLH Nobel's core strengths, and our equipment runs in most countries with a lumber industry. Getting each saw or setwork axis to land on target comes from pairing servo cylinders that have built-in feedback with high-response valves and a controller that profiles every move. Controlled acceleration and deceleration place the axis quickly and without overshoot, which protects board accuracy and yield. Because the same platform also manages force and pressure, the machine adapts as load and cutting resistance change shift to shift, keeping cuts consistent rather than chasing a moving target.
LVDT or magnetostrictive?
Both sensor types are proven in hydraulic servo cylinders; the right choice depends on the duty.
Absolute, for long strokes
Gives an absolute readout, suits very long strokes, and relies on an internal waveguide element.
Contactless, for hard duty
Used in our AC-transducers and the stainless-housed LMT variant, with linear ranges up to 1250 mm. It operates virtually friction-free, with no electrical contact to wear out, tolerates vibration and contamination well, and offers effectively infinite resolution. Inductive and contactless, it is hard to beat for high-cycle, high-vibration sawmill and heavy-machine duty.
Less mechanical wear, better accuracy
It can feel like a trade-off: push for speed and accuracy and you punish the mechanics. But a well-tuned servo axis delivers both. By profiling acceleration and speed instead of slamming to a hard stop, the system removes the shock loads, hammering and overshoot that wear out bearings, linkages and structures.
Gentler on the machine
The closed loop holds position under varying load without hunting, so there are no hard stops to hammer the structure.
Steadier output
Over thousands of cycles that means less maintenance, longer service life and output that protects both quality and uptime.
Beyond the sawmill
The same electro-hydraulic servo platform reaches well past lumber. Standard components are combined with customised engineering to lift the end result and the customer's efficiency.
Paper
Positioning, force and pressure control systems installed across paper-industry machinery.
Theatre
Smooth, accurate motion for stage machinery where reliability and quiet control matter.
Custom multi-axis
From a single replacement servo positioning unit to a complete multi-axis system designed around your machine, built from our POS-series cylinders, servo valves and feedback electronics.
Electro-hydraulic servo FAQ
What is an electro-hydraulic servo system?
It is a closed-loop system that combines servo cylinders, servo valves, position sensors and control electronics so hydraulic power becomes repeatable, controllable motion: the force of hydraulics with the accuracy and predictability of closed-loop control.
What is the difference between a servo cylinder and a standard hydraulic cylinder?
A standard cylinder simply extends or retracts until something stops it and has no idea where it is along its stroke. A servo cylinder carries an integrated displacement transducer, so it knows its exact position at all times, stops at any point on demand, and supports profiling and force or pressure regulation.
Should I use an LVDT or magnetostrictive position sensor?
Both are proven; the right choice depends on the duty. Magnetostrictive gives an absolute readout and suits very long strokes. LVDT, the BLH Nobel approach, is contactless and virtually friction-free, tolerates vibration and contamination, offers effectively infinite resolution and ranges up to 1250 mm, making it hard to beat for high-cycle, high-vibration duty.
Which industries use BLH Nobel hydraulic servo systems?
Sawmills are a core strength, with the same platform also used in paper-industry machinery, theatre and stage machinery, and custom multi-axis machines built around the customer's application.
Can I get a complete, pre-assembled system?
Yes. Systems are delivered pre-assembled in enclosures, cutting installation time and integration risk, and are ready to commission.
Does the system control force and pressure, or only position?
Both. It is a genuine force and pressure control system as well as a positioning system, so the machine can adapt as load and cutting resistance change.
Datasheets & the system around the axis
Put precise hydraulic motion to work in your plant
Tell us about your axis: stroke, load, cycle time and the accuracy you need. Our engineers will specify the servo cylinders, servo valves and control electronics to match, delivered pre-assembled and ready to commission.