Hydraulic Cylinder Position: In-Cylinder, External and Multi-Axis

A full guide to hydraulic cylinder displacement sensors: why the built-in magnetostrictive type is used, how the magnet ring rides with the piston and position is measured without contact, how to wire analogue four-wire and digital outputs, the four mounting rules for an oil cylinder, and how to set stroke, zero and direction. Includes a parameter table for built-in cylinder series and points to compare when choosing a brand.

300 bar, 600 peak: 19H overlaps Series 17. Platform, not accuracy; this in-cylinder magnetostrictive displacement sensor picks 19H for mixed duty.

An external magnetostrictive displacement sensor changes only a bracket. 19P shares Series 19; Series 18 fits followers better. Pick by that.

Five in-bore choices—16, 16R, 17, 17EX, 19H—split by gas, redundancy, platform. This magnetostrictive displacement sensor spans 12.7 mm to 600 bar.

By duty external families part—13 washdown, 18/19P follower, 19F long travel. This magnetostrictive displacement sensor line holds ±0.02% FS.

Calibrate head off the tube, oil kept. This integrated magnetostrictive displacement sensor takes M18x1.5, 600 bar, for purpose-built cylinders.

Two numbers decide Series 16: 12.7 mm bore, 350 bar, 530 peak. This in-cylinder magnetostrictive displacement sensor is sealed in oil; mind its 18G7.

Rate by pressure peak, not relief-valve. Series 16: 350/530 bar; 17 and 19: 600 bar. Match spike to this magnetostrictive displacement sensor.

Before cutting the piston rod: bore over 12.7 mm, depth past full stroke plus dead zone, concentricity held. This hole cannot be reworked once cut.

An external sensor leans on its bracket and slider. Keep the chain axial-only: rigid datum, parallel rail, floating slider. This tests bracket flex.

Injection molding means long strokes, hot oil. Pick in-cylinder versus external magnetostrictive displacement sensors for 0.5-3 m, 12.7 mm bores.

A servo valve circuit carries two position loops that are easy to confuse. The spool is held by the valve internal feedback and sets response speed. The cylinder needs an externally mounted magnetostrictive displacement sensor and sets where the load finally stops. With only the inner loop, flow offsets from load asymmetry and oil temperature cannot be corrected. This piece separates the two jobs, lists the four checks when selecting the outer unit, and covers the three mistakes most often made on site.

Servo-press accuracy is the slide loop. Clear +/-0.002 mm repeatability, 1-2 um resolution and fast update; in-cylinder plus bus synchronization wins.

Retrofit without opening the cylinder. Mount this magnetostrictive displacement sensor parallel to barrel, link a slider to rod end, or bend a 19F.

Two-platen retrofit, no cylinder cut? Fit an external magnetostrictive displacement sensor at the driven end: bracket, magnet, absolute off-encoder.

By the time stick-slip can be felt by hand, seals and guideways have usually been wearing for a while. A position curve shows it earlier, provided the curve is real rather than an artefact of sampling and filtering. Three shapes - staircase, sawtooth and a missing constant-velocity section - point to friction, flow pulsation and backlash, and each sends you down a different path. This article rules out the measurement side first, then reads the three shapes and sets the sampling rate, duration and trigger needed to capture something usable.

Every multi-cylinder sync scheme reduces to one of three: enforce it with structure, split the flow, or close a loop on position. All three work, in different territory. Mechanical sync is easiest when spans are short and strokes are small, a divider valve is enough when the load is symmetric and the tolerance loose, and servo closed loop becomes unavoidable once the load is asymmetric or the tolerance reaches a few parts in a thousand. A three-step test decides which applies.

When sync drifts out, the two most convenient actions on site are changing control parameters and swapping the magnetostrictive displacement sensor. Both are usually wasted effort. The correct order is bottom-up through four layers: mechanical backlash and distortion, then hydraulic split, leakage, oil temperature and trapped air, then mounting and calibration of the position feedback, and only then control parameters. A ten-minute static versus dynamic split narrows the direction first.

A tunnel shield steers from cylinder differences. Each magnetostrictive displacement sensor keeps absolute zero through slurry, long cables over bus.

Hydraulic-pitch blade angle comes from cylinder stroke. Absolute position under vibration, wide temp, EMI beats accuracy; in-cylinder IP67 offshore.

On diggers and loaders, survival beats accuracy. Strokes feed pose calculation in mud; pick in-cylinder Series 13, IP69K, CANopen, 25 g, 100 g shock.

Salt spray, roll, blackouts greet ship rudders. A magnetostrictive displacement sensor reads absolute angle, no homing; seal connectors, add backup.

Not every lift cylinder fits in-cylinder. Only a single-stage direct-acting plunger has a deep bore; telescopic cannot. Then go external.

Headers and seeders work in mud, washdown, winter storage. Map header lift, reel, down-force cylinders to in-cylinder mounting, IP69K, CANopen.

Compaction heads crash through leachate. This hydraulic cylinder displacement sensor sits in a deep 12.7 mm bore, rated 350-600 bar, off impact.