Technical Specifications

Main Features and Advantages

A stainless steel body that treats washdown as normal duty: The most important thing about the 871TM-DH8CN18-H2​ is not its sensing range but its survival. The 871TM line uses a stainless steel barrel and a stainless steel sensing face rather than a plastic or nickel-plated brass face, with mechanical seals at every opening and full epoxy potting of the electronics. The result is a sensor rated IP67 as standard and IP69K on the ToughLink cable version, capable of withstanding 1200 psi washdown. In a food processing plant that is cleaned with caustic foam and hot water twice a shift, or a machine tool flooded with synthetic coolant, this directly translates into fewer unexplained stoppages and fewer replacement cycles.ToughLink cable for flexing and dragging applications: The H2 suffix on the 871TM-DH8CN18-H2​ specifies a 2 m, 18 AWG, three-conductor ToughLink cable instead of the standard PVC option. ToughLink is a harder-wearing jacket material that resists abrasion, cutting fluids and repeated flexing far better than PVC, which is why this variant is specified on moving machine elements, robot end-effectors, tooling slides and anywhere the cable is likely to be dragged, pinched or exposed to oil. For maintenance teams, the difference shows up as a dramatic reduction in the most common proximity sensor failure mode of all — cable fatigue at the strain relief.Normally closed sinking output for fail-safe logic: The 871TM-DH8CN18-H2​ provides an NPN (sinking) normally closed output, meaning the output conducts when no target is present and opens when a target enters the sensing field. This is not an arbitrary catalogue variation. In a normally closed configuration, a severed cable, a failed power supply or a dead sensor all produce the same electrical state as “target present,” which the PLC interprets as a stop or alarm condition. For part-present verification, clamp-closed confirmation and guard or door position feedback, this behaviour is intrinsically safer than a normally open device, where a broken wire is indistinguishable from “part absent.”Diagnostic LEDs that reduce mean time to repair: Eighteen millimetre models such as the 871TM-DH8CN18-H2​ carry two LEDs: red indicates the output is energised, while green indicates power and flashes to warn of a short circuit condition. When a machine faults, the technician does not need to trace the input back to the PLC or open the panel with a multimeter — the state of two LEDs on the sensor body immediately distinguishes between “no power,” “output active,” “target detected” and “wiring fault.” On a line where every minute of downtime has a measurable cost, that diagnostic speed is a genuine financial argument, not a convenience.Electrical robustness that simplifies panel design: The 871TM-DH8CN18-H2​ includes protection against false pulse, transient electrical noise, reverse polarity, short circuit, overload and radio frequency interference, and tolerates capacitive loads up to 1 µF. In practical terms this means the sensor can be wired straight into a standard sinking PLC input without additional suppression components, it survives an accidental reversal of the supply leads during commissioning, and it will not be damaged by an output short — it will simply shut down, flash its green LED and recover once the fault is cleared. With ≤ 0.9 mA leakage current, it is also safe to use on high-impedance PLC inputs where excessive leakage could otherwise hold an input falsely on.