Comparing the Whole Cylinder-Integrated Range: How to Choose Among 16 / 16R / 17 / 17EX / 19H

Cylinder-integrated magnetostrictive displacement sensors have five selectable models: 16, 16R, 17, 17EX, 19H. They are all in-cylinder non-contact absolute sensors with piston-rod bore ≥12.7 mm (Ø10 rod). Accuracy and pressure are by series: 16/16R 16-bit D/A, 350/530 bar, cap Ø18G7; 17/17EX analogue infinite resolution, 350/600 bar, M18×1.5; 19H 300/600 bar. Do not write 1–100 μm / ±0.002 mm as one shared row. Selection therefore cannot rest on comparing data sheets; it must filter layer by layer on constraints: first explosion protection, then redundancy, then integration method and platform need, and only then ordinary adaptation.

Five cylinder-integrated products compared

First filter: is it an explosive-gas atmosphere?

This is the non-negotiable first item. Once the mounting point is classified as an explosive-gas hazardous area, the intrinsically safe 17EX must be chosen; the other four, however well they fit in performance, cannot be used. And “we bought an intrinsically safe sensor” does not mean the loop is intrinsically safe — a safety barrier/isolator must be fitted at the same time, and Uo≤Ui, Io≤Ii, Po≤Pi, Co≥Ci+cable capacitance, Lo≥Li+cable inductance must be checked item by item.

Full deployment of an intrinsically safe loop is in 17EX intrinsic safety explained; the basic distinction of explosion-protection types is in Intrinsic safety, flameproof and dust explosion protection distinguished; mapping of areas to certification is in Selecting for hazardous areas; wiring rules are in Installing in hazardous areas: intrinsically safe wiring and isolation barriers.

Second filter: is dual-channel redundancy needed?

If distortion of that position signal could injure people or cause major equipment damage (press slide position, lift height, mould-clamp position), choose 16R. Redundancy solves the failure mode “a slowly drifting wrong reading cannot be found” — with a single channel the controller has no comparison reference and can only treat the wrong value as truth.

When choosing 16R the comparison logic on the controller must be planned at the same time: tolerance-band width, duration criterion and fault-response action; none of the three can be omitted. Hardware redundancy without matching software comparison is equal to no redundancy. See Series 16R redundant cylinder-integrated explained; basic redundancy concepts are in What redundant output is; comparison methods for a dual-sensor scheme are in Redundant installation: how to compare and check two sensors.

Third layer: integration method and platform need

After the first two layers, 16, 17 and 19H remain. The criterion is mechanical integration and machine planning:

• Cylinder customisable to the sensor interface, and volume supply → Series 17. Highest integration, least external protrusion, good assembly consistency. The cost is that substitutes are limited by the interface; see Series 17 explained.
• Several classes of measuring point on the machine — in-cylinder, external, high-temperature split — and unified spares and procedures wanted → 19H. Same platform as the 19D split type, 19P external type and 19F flexible type; see 19H cylinder-integrated explained.
• Cylinder already frozen, or a wider adaptation surface needed → Series 16. Highest adaptation flexibility; the default cylinder-integrated choice; see Series 16 explained.

Three hard constraints common to all cylinder-integrated types

Bore. Piston-rod minimum diameter ≥12.7 mm (Ø10 rod; Series 16 cap Ø18G7, Series 17 M18×1.5), bore depth covering the full stroke plus non-measuring-section allowance; the key figure is straightness, not wall finish (the sensing rod does not contact the wall). On a small rod diameter with high side load, strength margin after boring may be insufficient — that is a mechanical problem, and choosing a sensor will not solve it. Machining requirements are in Bore machining requirements for cylinder-integrated sensors.

Pressure rating. Choose 350/530 bar (16), 350/600 bar (17), 300/600 bar (19H) on system peak pressure, not on the relief-valve set point. Pressure shocks from reversing, emergency stop and sudden load change can be well above the set point. Calculation methods are in Selecting for high-pressure cylinders.

Oil temperature. Cylinder-integrated types are immersed in hydraulic oil for long periods, so oil temperature is the working temperature. When oil temperature is high, check the specification and consider speed-of-sound temperature drift; see Speed-of-sound temperature drift and compensation and Operating temperature vs. storage temperature. If the specification is exceeded, consider the same-platform 19D split type to move the electronics head out of the high-temperature zone; see 19D split type explained.

When a cylinder-integrated type should not be chosen at all

The greatest cost of a cylinder-integrated type is that replacement means depressurising, draining and stripping the cylinder. The following cases should turn to an external option:

• The cylinder is a standard bought-in part and cannot be bored;
• Equipment availability requirement is high and stripping-cylinder downtime cannot be accepted;
• Retrofit of existing plant; the mechanical body must not be touched;
• Mobile machinery working outdoors, with poor field repair conditions.

Selection of external options is in Comparing the whole external range: how to choose among 13/18/19P/19F; overall decision for retrofit projects is in Selecting for retrofit of existing plant. Background on magnetostrictive sensing in hydraulic equipment is in Why choose magnetostrictive sensing for hydraulic cylinder position control.