Automation and plant engineering

In depth: Automation and industrial process ↑ up

In industrial automation and process control, a reliable speed and length measurement is the basis for synchronising drives, controlling cutting and documenting production. ASTech velocimeters and optical encoders provide this measurement without contact, integrating easily into existing automation systems.

This section brings together solutions for in-line measurement and process automation. For the technical principles, please refer to the Technologies section; the other application areas are covered in Steel and metals, Paper, printing and converting and Wood, furniture and flooring.

Measurement as the basis of automation

An automation system is only as reliable as the data it is based on. The speed and length of the material feed critical functions such as cut-to-length, piece counting, synchronisation between rollers and drives, and the control of continuous processes. If this data comes from a measuring wheel subject to slippage and wear, the entire control chain suffers. A non-contact optical measurement, by contrast, provides a stable reference that is repeatable over time, on which the automation system can rely.

The VLM500 offers high speed and high accuracy (up to 50 m/s, uncertainty < 0.025 %), while the VLM60 replaces measuring wheels directly and measures down to 0 m/s, making it ideal for slow movements with frequent starts and stops.

Solutions for process automation

Optical solutions apply to a wide range of continuous and discrete processes, from in-line measurement to the synchronisation of conveyors and drives. The dedicated page examines non-contact measurement directly on the production line in more detail.

Advantages for automation

• A stable, repeatable speed and length reference
• Encoder, analogue and fieldbus outputs for easy integration
• Fast update time for control loops
• No wear: reliable data in continuous operation
• Direct replacement for measuring wheels and rotary encoders

Integration with PLCs and fieldbuses

ASTech instruments provide A/B incremental encoder outputs, an analogue current output and the main industrial fieldbuses, such as Profibus DP, Profinet IO and EtherNet/IP. Integration with PLCs, drives and supervisory systems is consequently simple and standardised. In many cases the optical speed meter directly replaces a measuring wheel or a rotary encoder, replicating its signal: the technology upgrade therefore does not require the control architecture to be redesigned.

The update time of less than one millisecond also makes the signal suitable for the fastest control loops, where the responsiveness of the data affects the quality of the control.

Reliability and availability

In an automated plant, availability is everything. The absence of contact parts eliminates wear and periodic maintenance, while the IP 65 protection rating ensures reliability in industrial environments. The measurement consequently remains stable over time and unplanned downtime is reduced. Ultimately, the optical solution improves the quality of process control and lowers the total cost of operation, with a rapid return on investment. RODER technical support assists the customer in choosing the model and in integration.

Recommended products

Sectors and processes served

Optical speed and length measurement is used across the board in automated processes: continuous rolling lines, converting, woodworking, plastics and rubber extrusion, cable and pipe production. In all these cases the optical speed meter provides the speed reference on which the automation system builds its own control loops. The same technology consequently becomes a standard component of process automation in very different sectors.

LED light and safety

ASTech instruments use white LED illumination, not laser. This removes the safety requirements typical of higher-class laser systems and simplifies installation in environments where operators are present. The absence of coherent light also avoids speckle, improving measurement stability on irregular surfaces. For this reason the solution is particularly suited to automation cells and attended lines.

Scalability and standardisation

Adopting a single measuring principle across several lines and processes makes it possible to standardise spare parts, procedures and skills. From the point of view of scalable automation, this reduces complexity and indirect costs and speeds up adoption on new plants. The data, available on encoder, analogue and fieldbus outputs, integrates uniformly into the various control systems.

From measurement to control

In automation, the value of a measurement lies in the actions it enables. A reliable speed makes it possible to trigger shears at exactly the right instant, keep the ratios between drives constant and regulate continuous processes without drift. Optical measurement, stable and responsive, provides this reference for the whole life of the plant, without the wear that affects contact-based solutions. RODER technical support assists the customer from the choice of model through to commissioning and integration with the control system.

Frequently asked questions

Why use optical measurement in automation?

Because it provides a stable, wear-free speed and length reference on which to base cutting, counting and synchronisation, improving the reliability of the control.

How does it integrate with the PLC?

Through incremental encoder outputs, an analogue output and fieldbuses (Profibus DP, Profinet IO, EtherNet/IP), compatible with existing automation systems.

Can I replace a rotary encoder or a measuring wheel?

Yes. The optical speed meter replicates the encoder signal, so it directly replaces measuring wheels and rotary encoders without redesigning the control.

Is the signal suitable for fast control loops?

Yes. The update time of less than one millisecond makes the data suitable even for the fastest control loops.

Which model should I choose?

The VLM500 for high speed and high accuracy; the VLM60 for low speeds, starts/stops and the direct replacement of measuring wheels.

Monitoring rotational speed

In addition to measuring the speed and length of materials, process automation includes RPM monitoring of rotating machinery. Stroboscopes measure rotational speed without contact and allow moving parts to be inspected, for process control and predictive maintenance.