NOVOTECHNIK Angular Position Sensor Encoder Rotary Sensor IP-6501-A502 IP6501A502 IP-6501-A502

Novotechnik IP-6501-A502 | Rotary Shaft Potentiometer — 355°, 5kΩ, ±0.075% Linearity, IP65, Conductive Plastic, 100 Million Cycles, −40°C to +100°C

Overview

The Novotechnik IP-6501-A502 is a rotary shaft potentiometer from Novotechnik's IP6000 industrial series, covering a 355° electrical rotation range with a 5kΩ conductive plastic resistance element and ±0.075% independent linearity.

It translates shaft angular position into a proportional analogue voltage output through the voltage divider principle — the output voltage at the wiper is directly proportional to the shaft's angular position within the 355° electrical travel, making it a straightforward interface to any analogue input channel, signal conditioner, or position controller that accepts a resistive or ratiometric voltage output.

Novotechnik built the IP6000 series around three engineering priorities that matter in industrial position sensing: long service life without recalibration, resistance to the environmental conditions of machine tool and industrial machinery locations, and the accuracy that closed-loop position control requires.

The conductive plastic resistance element achieves all three simultaneously. Unlike wire-wound potentiometers whose wiper tracks individual wires and generates electrical noise at each contact crossing, the conductive plastic surface is continuous — the wiper moves across a smooth, uniform resistance track with no step changes, no cross-wire noise, and negligible mechanical wear per cycle.

The result is a potentiometer rated for 100 million mechanical cycles — a service life that translates to decades of reliable operation in most machine applications. A machine cycling its position axis 1000 times per day would take over 270 years to reach 100 million cycles.

This figure is not a theoretical limit but a tested characteristic of the conductive plastic technology that makes Novotechnik's sensors a standard component in long-life industrial machines.

Key Specifications

Conductive Plastic Resistance Element — Why It Matters

The choice of conductive plastic over wire-wound construction is the fundamental specification decision that determines this potentiometer's fitness for precision industrial applications.

Wire-wound elements generate small voltage steps as the wiper moves from wire to wire, producing a resolution limit equal to one wire pitch — typically 0.05° to 0.5° depending on the winding density.

They also generate impulse noise at each wire crossing, which can interfere with sensitive analogue input circuits and cause control system instability.

Conductive plastic elements have no such resolution limit — the output voltage changes continuously and smoothly with angular position, with resolution limited only by the analogue-to-digital converter reading the signal.

This makes the IP-6501-A502 appropriate for closed-loop position control applications where fine position increments must be resolved accurately, and where the noise immunity of the position signal directly affects control loop stability.

The wear characteristic of conductive plastic is also fundamentally different from wire-wound. Wire-wound elements wear through mechanical abrasion of the wiper against the wires, creating resistance changes and eventually open circuits at heavily used positions.

Conductive plastic wears uniformly across its surface, with the precious metal multi-finger wiper assembly distributing contact force and prolonging both element and wiper life simultaneously.

±0.075% Linearity — Angular Position Accuracy in Practice

The linearity specification of ±0.075% means the worst-case deviation of the actual wiper voltage from a perfect straight line connecting the two end-stop voltages is no greater than 0.075% of the full-scale voltage range.

For a 355° electrical range at 10V full-scale excitation, this represents a maximum position error of 0.27°. For a 5V excitation, the maximum voltage error is 3.75 mV.

This is the independent linearity figure — the straight line is best-fit to the actual transfer curve, not end-to-end.

For applications where the end-to-end linearity matters (when the device is used ratiometrically with the supply voltage as reference), the figure may differ slightly.

The 0.007° repeatability is a separate specification confirming that the sensor returns to the same electrical output at the same mechanical position — small enough to be irrelevant in any application where the ±0.075% linearity is acceptable.

IP65 Sealed Housing and Stainless Steel Shaft

The IP65 rating covers complete dust exclusion and protection against water jets — appropriate for the machine tool environments where position feedback sensors typically mount. The stainless steel shaft with sealed passage is the design detail that makes IP65 achievable at the shaft exit: a standard shaft-to-housing clearance would be an open path for contamination; the sealed passage closes this gap without adding friction that would increase starting torque above the <1.5 Ncm specification.

The anodised aluminium housing provides corrosion resistance and dimensional stability across the −40°C to +100°C operating temperature range.

Aluminium's thermal expansion coefficient differs from steel, but the housing dimensions at both extremes of the temperature range remain within the tolerances required for mechanical fit with the mounting flange and shaft coupling.

Applications: Where Rotary Potentiometers Outperform Encoders

For applications that require a simple, direct analogue position output without the pulse counting, homing, and battery backup complexity of incremental or absolute encoders, a high-quality rotary potentiometer like the IP-6501-A502 is the appropriate choice.

Control valve position feedback, throttle position sensing, antenna elevation control, crane hook angle measurement, and steering angle feedback in industrial vehicles are all applications where an analogue voltage directly proportional to angle is more convenient than a digital pulse count that must be converted to angle in software.

The 355° electrical range — leaving a 5° mechanical dead band at the wrap-around point — is compatible with most rotational position sensing tasks that do not require continuous 360° measurement.

For continuous rotation monitoring, the IP-6501-A502 is not appropriate (it has an electrical dead zone); for single-turn and partial-rotation applications within ±177.5° of centre, it is an excellent fit.

FAQ

Q1: What is the "A502" variant designation, and what does it mean for resistance?

The A502 designation specifies the nominal resistance value. In Novotechnik's IP6000 series coding, "502" corresponds to 5kΩ (5 × 10²). Other resistance values are available in the IP6501 series for different source impedance requirements.

The 5kΩ resistance is a balance between providing enough resistance to minimise power dissipation at 42V maximum supply (at 42V, total element current is 8.4mA) and keeping the source impedance low enough that the wiper circuit's ≤1 µA recommended current does not cause loading error at the analogue input.

Match the resistance to the input impedance of the receiving circuit.

Q2: Can the IP-6501-A502 be used as a 4–20mA transmitter output?

No. The IP-6501-A502 is a passive voltage divider — it provides a ratiometric voltage output, not a current output. Connecting it to a 4–20mA loop requires a separate signal conditioner or transmitter module that supplies the excitation voltage to the potentiometer and converts the wiper voltage to a 4–20mA loop current proportional to position. Novotechnik and other manufacturers offer compatible transmitter modules for this conversion.

Alternatively, many PLC analogue input modules accept direct potentiometer (resistance) or ratiometric voltage inputs that work directly with the IP-6501-A502 without signal conditioning.

Q3: How is the IP-6501-A502 mechanically coupled to the rotating shaft being measured?

The IP-6501-A502's own shaft must be coupled to the rotating element being measured. For angular position measurements where the sensor mounts to a fixed structure and the measured shaft passes through a coupling to the sensor shaft, a flexible coupling is recommended to absorb misalignment between the sensor shaft and the measured shaft.

Rigid couplings transmit bending forces to the sensor shaft when misalignment exists, which can increase starting torque and accelerate bearing wear. The <1.5 Ncm starting torque specification assumes the sensor shaft is properly aligned and carries no significant side load.

Q4: What happens at the 5° dead band between 355° and 360°?

At the end of the 355° electrical travel, the wiper leaves the conductive plastic track and enters a dead zone where the output is undefined.

In applications where the shaft may rotate past 355° from the zero position, the control system must handle this transition — typically by limiting travel mechanically to remain within the 355° electrical range, or by detecting the transition and handling it as an out-of-range condition. 

The IP-6501-A502 supports continuous mechanical rotation (360° and beyond), but the electrical output is only defined for the 355° ± 2° range.

Q5: What connector type does the IP-6501-A502 use, and what is the pin assignment?

The IP-6501-A502 uses a 5-pin connector at the electrical connection point. The pin assignment follows Novotechnik's standard: typically two pins for the element ends (excitation supply and return), one pin for the wiper output, and two additional pins for the housing ground and spare/shield connection.

The exact pinout is documented in Novotechnik's IP6501 series data sheet. The mating connector is a standard 5-pin circular type — confirm the shell size and contact arrangement from the data sheet before specifying the cable assembly.