On a hydraulic press, clamp, or mobile boom, cylinder stroke is not a nice-to-have signal—it is often the only clean way to know where the tooling sits before the next step fires. Analog limit switches and incremental encoders struggle when the same axis sees high pressure, shock, and contamination. That is why machine builders keep returning to magnetostrictive linear displacement transducers (LDTs) embedded in sensor-ready cylinders.

Ametek Factory Automation has extended its GEMCO 953 family with the 953I: the same non-contact rod-style architecture, now with native IO-Link so position, diagnostics, and parameters can ride a standard three-wire drop into an IO-Link master instead of a dedicated analog or SSI card.

GEMCO 953I head shows the IO-Link branding and M12-style face connector used for process data and service parameters.

What stays the same on the 953 platform

Mechanically, the 953I does not reinvent the probe. A current pulse travels the waveguide; a sliding magnet on the piston returns the absolute position without wear surfaces inside the oil volume. The sensor screws into a prepared cylinder port, seats on an O-ring, and places the sensing rod down a minimum ~0.5 in bore through the piston stack (spacer, 4-hole magnet, optional bushing).

Family specs that matter on the floor remain: roughly 0.00006" measurement resolution, 7–30 VDC supply, and IP68 sealing aimed at both factory cells and mobile hydraulics. Those numbers are why plants already standardized on 953A analog, 953D digital, or 953S SSI units can treat 953I as a connectivity option rather than a new mechanical redesign.

Cylinder cross-section: GEMCO head outside the barrel, waveguide through the rod bore, magnet fixed to the piston for non-contact absolute feedback.

Why IO-Link changes the service story

Cyclic process data alone is not the whole pitch. IO-Link also exposes parameterization and device diagnostics to the PLC or an HMI through the master’s IODD tooling. Field techs can confirm health, adjust setup, and pull identity without a proprietary handheld or special service cable—useful when the cylinder sits on a vehicle or in a pit where laptop time is expensive.

For OEMs already standardizing IO-Link on proximity, pressure, and RFID, a 953I channel collapses another specialty interface into the same cabinet practice. Brownfield panels can keep analog or SSI SKUs on identical mechanical envelopes while new machines migrate to 953I.

Mobile hydraulic cylinder: the class of high-force, outdoor axis where IP68 absolute feedback and remote diagnostics earn their keep.

Hydraulic sequences that need continuous stroke data

Hydraulics win when force density matters—clamps, buckets, mold halves, press platens. Knowing only “fully out” or “fully in” is rarely enough. On a press, building tonnage before or after the correct point in the stroke can scrap the part even if peak pressure looks normal on a gauge.

A continuous LDT lets the controller gate sequences on true position: enable pressure only inside a window, reject a cycle that never reached the join point, or raise a fault when the magnet signal disappears. One well-mounted absolute channel often replaces a handful of discrete checks. With IO-Link, that channel also reports when the device itself is the problem.

Wire absolute cylinder feedback into the same project as your PLC and PAC systems, and keep related rotating-asset protection under Bently Nevada when the machine train carries both closed-loop hydraulics and condition monitoring.