Novotechnik Multi-Turn Rotary Sensors: MB1, MC1, MZ1 and RMB Compared

A single-turn rotary sensor measures position within one revolution. Turn the shaft past 360 degrees and it starts again at zero. For a valve actuator or a throttle that is exactly right. For a crane hoist, a leadscrew, a winch or a steering column, it is useless — you need to know which revolution you are on.

That is what a multi-turn sensor provides, and the interesting question is how it remembers.

True-Power-On: why it matters

Traditional multi-turn designs count revolutions. That works while powered. Remove the power and the count has to be preserved somehow, which historically meant one of two compromises:

A battery, which keeps the counter alive. Batteries fail, and when one does the position is lost — usually discovered at the worst moment, and requiring a re-reference before the machine can move safely.

A mechanical gear train, which stores the turn count physically. No battery, but gears add size, backlash and a wear mechanism.

Novotechnik NOVOTURN technology takes a third route. The sensor determines absolute position across the full multi-turn range at power-up, without a battery and without a gear train. If the shaft is moved while the power is off — by hand, by gravity, by a load slipping — the sensor reports the true new position when it powers up, not the position it remembers.

For anything where an unexpected movement during a shutdown is possible, this is the difference between resuming safely and needing a manual re-reference.

The four series

MB1-3600 — absolute non-contacting multi-turn with True-Power-On NOVOTURN, in a 36.5 mm all-metal housing. The all-metal construction is the reason this one gets specified for rough duty. Available with CANopen and IO-Link.

MC1-2800 — NOVOTURN multi-turn with smart sensor functions, in a more compact 28 mm format. Also available with CANopen and IO-Link. The choice where space is constrained.

MZ1-2200 — NOVOTURN multi-turn with smart sensor functions in the smallest format of the three, 22 mm. CANopen available. For tight installations where an MC1 will not fit.

RMB-3600 — absolute non-contacting NOVOHALL multi-turn in a 36.5 mm all-metal housing, with analogue and digital interfaces and several versions available. NOVOHALL rather than NOVOTURN, so confirm the power-off behaviour against your requirement if the shaft can move during shutdown.

Smart sensor functions

The MC1 and MZ1 carry what Novotechnik describes as smart sensor functions. In practice this means parameters that would traditionally be fixed at manufacture — measuring range, zero point, direction of rotation, output scaling — can be configured rather than ordered.

Two consequences worth planning around. Commissioning gets faster, because the sensor is adjusted to the machine rather than the machine to the sensor. And spares holding gets simpler, because one configurable part can cover several positions that would otherwise need distinct part numbers.

If you hold spares across a fleet, ask about this specifically — it often reduces the number of variants you need to stock.

Choosing between them

1. Start with the housing size. 36.5 mm, 28 mm or 22 mm. Mechanical space usually decides this before anything else does.
2. Then the interface. CANopen across all three NOVOTURN series, IO-Link on MB1 and MC1, analogue and digital on RMB.
3. Then robustness. The all-metal 36.5 mm housings of MB1 and RMB suit exposed and mobile applications.
4. Then configurability. If you want smart sensor functions, MC1 or MZ1.

Where multi-turn is the right answer

• Crane and hoist position — drum rotation over many turns, where the load position must be known immediately at power-up
• Leadscrew and spindle position — linear motion driven through many revolutions
• Winch and cable drums
• Steering angle on mobile machinery, where lock to lock exceeds one turn
• Multi-turn valve actuators — gate and globe valves that take many turns to stroke
• Roll gap and screwdown adjustment in rolling mills

The common thread is that the mechanism travels through more than one revolution and the machine has to know where it is without a homing move.

When a single-turn sensor is enough

If total travel stays within one revolution, use a single-turn sensor — it is simpler and cheaper. The single-turn range covers that, including the RSC-2800 and RFC-4800.

Where a gearbox reduces a multi-turn mechanism to under one revolution at the measuring point, a single-turn sensor also works — but check the backlash, because it appears directly in your position reading.

Specifying

Send us the total number of revolutions, the resolution required, whether the shaft can move while the power is off, the interface your controller expects, the mechanical arrangement and available space, and the protection rating needed. Accent is the sole authorised Novotechnik distributor for India and SAARC.