Safe Motion

Keep the machine safe without switching it off

Removing power is not always the safest or most productive response. Where an operator must observe, thread, teach or adjust while the machine moves, the movement itself has to be monitored — safe standstill, safe speed and safe direction, proven by the control system rather than assumed.

Safe standstill Safely limited speed Safe direction PNOZ s30 · PMCprotego

Discuss Safe Motion Requirement Compare Motion Architectures

PL eAvailable on selected routes

SIL CL 3PNOZ s30 capability

Feedback-basedEncoder or sensor required

Diagram of the safe speed range monitoring function used in Pilz safe motion applications

Safe speed rangeOne of several monitored motion functions

PL ePNOZ s30 and PMCprotego

SIL CL 3PNOZ s30

StandstillMonitored, not timed

DirectionSafe direction of rotation

By safety function

Safety technology selection by application

Organise the decision around the motion function the machine actually needs, then decide where that function should be evaluated — externally, in the safety controller, or inside the drive.

Standalone

External monitoring

PNOZ s30

A stand-alone speed monitor that watches the drive independently of it, which suits machines where the existing drive cannot be relied upon for the safety function.

Safe monitoring of speed, standstill, position and direction of rotation
Speed range monitoring and broken shear pin monitoring on drives
Applications up to PL e and SIL CL 3
Independent of the drive manufacturer, subject to feedback compatibility

Best fitRetrofit, mixed drive brands, or drives without safe functions.

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Controller module

Pilz PNOZmulti 2 controller with motion-monitoring module capability

Integrated in the controller

PNOZmulti 2 motion monitoring

Motion-monitoring modules bring the speed and standstill functions into the same configurable controller that already evaluates the guards and stops.

Motion monitoring alongside the other machine safety functions
One project, one configuration and one diagnostic picture
Suits machines already using PNOZmulti 2
Module and feedback compatibility to be confirmed per project

Best fitMachines where guards and motion interact, such as safe setup modes.

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Drive integrated Diagram of the safe operating stop function used in drive-integrated safe motion

Inside the drive

PMCprotego Safe Motion

A safety card within the drive, so the motion safety functions are evaluated where the motion is generated. The manufacturer states the drive achieves up to PL e of EN ISO 13849-1 with common motor feedback systems and fieldbuses.

Drive-integrated safety card rather than an external monitor
Up to performance level PL e, and SIL 3, per manufacturer product information
Reaction is local to the drive, without external wiring loops
Confirm the current PMC family and drive compatibility for the project

Best fitNew machine designs specified around drive technology.

Brake safety

Diagram of the safe direction monitoring function in Pilz safe motion applications

Holding the load

Safe brake control

On gravity-loaded axes the brake is part of the safety function, so its control and its condition both need to be addressed rather than assumed.

Safe control of the holding brake as a distinct function
Brake condition testing where the application requires it
Relevant to vertical axes, presses and suspended loads
Confirm the current manufacturer brake-control device for the application

Best fitVertical and gravity-loaded axes that must be held, not merely stopped.

Function diagrams shown.The images above are function illustrations for monitored motion states, not photographs of specific devices. Device renders follow the selected product.

Architecture selection

Decide where the motion function is evaluated

The same safe speed function can be implemented in three places. The right one depends on whether the drive is fixed, whether the machine is new, and who owns the validation.

Criterion	External monitoring	Controller module	Drive integrated	Safe brake control
Typical product	PNOZ s30	PNOZmulti 2 motion	PMCprotego Safe Motion	brake-control route
Drive dependency	Largely independent	Largely independent	Tied to the drive family	Brake and axis specific
Best for	Retrofit, mixed brands	Machines already on PNOZmulti 2	New designs on drives	Gravity-loaded axes
Feedback	Encoder or sensor to the monitor	Encoder or sensor to the module	Motor feedback to the drive	Brake feedback and testing
Wiring effort	Separate device and feedback run	Within the existing controller	Least external wiring	Additional brake circuit
Main consideration	Feedback compatibility	Module availability	Drive family commitment	Brake condition over life

Do not assume an existing drive provides safe functions. A drive with a stop input is not automatically capable of a rated safe motion function. Drive model, firmware, feedback system and certification must be verified before a safe speed or standstill function is credited to it.

Applications

Monitored motion changes the outcome

In each case the productivity gain comes from allowing controlled access instead of a full stop — but only where the movement is genuinely monitored.

Operator intervention during packaging machine setup with monitored safe motion

Setup and changeover

Machine setup at reduced speed

Threading, format changes and adjustment need the machine to move while someone is close to it, at a speed proven to be within the safe limit.

Typical routeSafely limited speed with an enabling device.

Safe operating stop function keeping an axis in position under monitoring

Access after stopping

Standstill before guard release

Rather than releasing a guard on a timer, the guard stays locked until standstill is actually monitored, which removes the guesswork from long run-down.

Typical routeStandstill monitoring interlocked with guard locking.

Safe direction monitoring preventing movement in the hazardous direction

Directional hazard

Movement only away from the operator

Where the hazard exists in one direction only, monitoring direction allows productive movement to continue while the dangerous direction stays blocked.

Typical routeSafe direction monitoring in the motion architecture.

Before selection or quotation

Engineering prerequisites

Safe motion depends on mechanical facts as much as electrical ones. Without these the function cannot be sized or validated.

The motion function

Which function is required — standstill, limited speed, direction or position
The safe speed or standstill threshold, and its tolerance
Whether the function applies in all operating modes or only in setup
Target performance level or safety integrity level, if determined

Drive and feedback

Drive manufacturer, model and firmware
Whether the drive already offers rated safe functions
Encoder or sensor type, resolution, signal and cabling
Whether a second, diverse feedback source is required

Mechanics and response

Measured run-down time and distance from operating speed
Load, inertia and whether the axis is gravity loaded
Brake type, and whether the brake forms part of the safety function
Total reaction time from detection to safe state

Access and operation

How access during monitored movement is granted and revoked
Whether an enabling device is required, and where it is held
Operating-mode selection and how modes are secured
Validation evidence required for each mode

Related systems

Safe motion is a chain, not a device

Feedback, evaluation, the drive response and the mechanical brake all sit inside the safety function. The calculated reaction time has to include every one of them, and be proven on the machine.

Encoder or sensor feedback

PNOZ s30 or controller module

Guard locking released on standstill

Enabling device for setup mode

Operating-mode selection

Brake control and testing

Monitored intervention on a packaging machine during setup

Modernising an existing machine?Retrofit routes across the complete safety portfolio, including what can justifiably remain in place, are set out inMachine Safety Retrofit & Modernisation.