Series 16 Cylinder-Integrated Explained: Bore Requirements and Pressure Limits

Series 16 is Germanjet’s cylinder-integrated magnetostrictive displacement sensor. The sensing rod is fitted from the cylinder base into a bore in the piston rod, and the magnet ring moves with the piston. Displacement sensing is sealed entirely inside the cylinder: it occupies no external space and is unaffected by external impact or wash-down. It also brings two hard engineering limits: rod Ø10.0 mm, cylinder cap Ø18G7 (machine Ø18F7), piston-rod bore ≥12.7 mm; and in-cylinder pressure 350 bar working / 530 bar peak. These two limits decide whether Series 16 can be used at all, and come before any accuracy figures.

Electrical outputs: 160 voltage, 161 current, 162 SSI (binary / Gray, RS422). 192 is Series 19 SSI — do not mix it with 162.

How the cylinder-integrated construction works

Cylinder-integrated and external types differ only in mounting position; the measuring chain is identical: the electronics head launches a current pulse along the waveguide wire, which meets the magnet-ring field and generates a torsion stress wave; the echo travel time is converted into absolute position. The principle is set out in Magnetostriction and the Wiedemann effect.

The distinctive feature of Series 16 is that the sensing rod is a pressure-containing sealed structure, mounted on the cylinder-base end cover by a flange or thread, with the rod immersed in hydraulic oil. The magnet ring is usually a ring magnet press-fitted on the piston, or a dedicated magnet carrier matched to the piston bore. There are no exposed moving parts, so typical external-type problems such as “bracket resonance” and “magnet-ring collision” almost never arise in the field.

Bore and cylinder-cap machining: Series 16 uses Ø18G7, not Series 17’s M18

Both Series 16 and 17 go inside the cylinder, but the cylinder-cap interface is not the same drawing.

Series 16 cylinder cap . Sensor insertion bore Ø18G7, machine the cap to Ø18F7, lead-in 15°±1° / 45°±5°, seal groove as on the drawing (e.g. 15.4×2.1). Electronics housing OD about 79 mm, bolt circle 64 mm, 6×Ø6.4 mounting holes. Rod Ø10.0 mm, rod-end blind zone about 63.5 mm. The bore axis must be concentric with the piston rod.

Piston-rod bore. The Ø10 mm rod must pass without friction. piston-rod drilling ≥12.7 mm on the Series 17 pages; Series 16 uses the same Ø10 rod, so use the same lower limit. An oversize bore does not break non-contact measurement, but it weakens the piston rod and must be checked in the hydraulic design.

Bore depth and straightness. Depth must cover the full stroke plus the non-measuring section (including the rod-end blind zone). If the deep hole wanders, the magnet ring goes eccentric and the reading drifts over a local section of stroke. The wall does not need grinding — control straightness. Acceptance is in Bore machining requirements for cylinder-integrated sensors.

Series 17 is a different cap: seating face ≥Ø35 mm, roughness Rmax 1.6, through-hole Ø13 mm, M18×1.5 thread, null zone 50 mm, dead zone 60 mm. Do not put Series 17 thread dimensions into a Series 16 flange bore.

Pressure limits: Series 16 is 350 / 530 bar — do not write 300 / 600

The common selection error is to choose on rated system pressure rather than peak pressure. Hydraulic systems produce pressure shocks on reversing, emergency stop and sudden load change; the instantaneous peak can be well above the relief-valve set point. If the system has no accumulator or cushion valve, the peak pressure must be confirmed by measurement. The full calculation for high-pressure duty is in Selecting for high-pressure cylinders.

Series 16 versus an external solution

The conclusion is direct: new-machine design with a customisable cylinder → prefer cylinder-integrated; retrofit of existing plant or a standard bought-in cylinder → prefer external. Forcing a cylinder-integrated type onto a standard cylinder often means re-buying a custom cylinder, and the conversion cost far exceeds the sensor itself. See the Series 16 product page and Series 18 external type explained.

How Series 16R, 17 and 19H divide the work

The cylinder-integrated line has further splits: where dual-channel redundant output is needed to meet safety requirements, choose the Series 16R redundant type; its safety design is explained in Series 16R redundant cylinder-integrated explained. Three independent measuring chains: 16T. Salt spray, immersion, high-pressure wash: 16E (cap and pressure stay Series 16). Where the cylinder construction and mounting interface differ and an integrated solution is required, compare Series 17; the core differences are listed item by item in Series 17 explained. Explosive-gas atmospheres must use the intrinsically safe 17EX. Horizontal selection across the whole cylinder-integrated line is in Comparing the whole cylinder-integrated range.

Electrical outputs: 160 / 161 / 162 — not 192

Series 16 has three electrical outputs: 160 voltage, 161 current, 162 SSI (binary or Gray, 8–32 bit, 1 / 2 / 5 / 10 / 20 / 50 / 100 μm, 7-pin D70). 192 is Series 19 SSI; cap and pressure are a different set. See 162 SSI vs 192 SSI.

Analogue update time by stroke: ≤1200 / 2400 / 4800 / 7600 mm → 0.5 / 1.0 / 2.0 / 5.0 ms, see refresh rate vs control cycle. 162 update rate vs stroke: 3.7 kHz at 300 mm, 0.5 kHz at 5000 mm.

Connectors: 160 / 161 use internal terminals; 162 uses D70. Wrong pin count: DIN 43650 / D60 / D70 / M12.

Pre-installation checklist

• Piston-rod bore ≥12.7 mm; cap Ø18G7 (machine Ø18F7, lead-in 15°±1° / 45°±5°); electronics housing about 79 mm OD, bolt circle 64 mm, 6×Ø6.4; rod-end blind zone about 63.5 mm;
• Deep-hole straightness verified, especially on long-stroke cylinders;
• System peak pressure below the selected pressure rating;
• Cylinder-base port thread/flange form and sealing face machined correctly; O-ring groove to specification;
• Magnet-ring assembly coaxial; magnet polarity fitted as in the instructions;
• Dead-zone allowance at both ends of stroke so the magnet ring does not enter the invalid region; see Dead zones at both ends of the measuring range.

Hydraulic-oil cleanliness also affects long-term reliability — metal swarf in the oil is attracted to the magnet ring, and a long-term build-up can disturb the field distribution. Maintenance advice is in Installation and commissioning in practice.