A robot uses a suction gripper to move separator plates between the handling lift of the vertical storage system and the roller conveyor.

© Rotte

It is the drives that Rotte uses to power the entire material flow for the production of technical laminates. To this end, a manufacturer from the Black Forest builds presses that laminate individual sheets of material under pressure and temperature to create multi-layer printed circuit boards for the electronics industry. Rotte takes care of all the handling involved in loading and unloading the presses as well as the upstream and downstream material flow. Flexibility is required. For the conveyor technology manufacturer, this means that the controllers can be used for both open-loop and closed-loop applications.

Decentralized drive technology

Example of a remote solution consisting of a geared motor and decentralized Movimot.

© SEW/Sienk

The motion control converts commands from the higher-level PLC into positioning in conjunction with the integrated multi-turn absolute encoders. The computing intelligence thus relieves the control system. Because the motion control is defined separately from the control level, the motion control also forms the basis for configuring system modules independently.

Connection box for two cables

The advantages become clear when looking at the past: until now, a control cabinet measuring 760 × 600 × 250 mm³ was required for the drives of a lift. Instead, a small junction box for two cables for the power supply and Profinet communication hangs further down on the self-sufficient modules. Everything else is decentralized. Another advantage is the flexibility of the drives at I/O level: all three versions of the Movimot collect the signals from the sensors installed in their immediate vicinity in the material flow system. The signals are bundled and transferred to the system control via Profinet. Regardless of the number of sensors, this design creates a standard interface and also helps to save on cables during installation.

Decentralized inverter as a decentralized I/O station: The Movimot collects the signals from the sensors in the immediate vicinity and sends them bundled via Profinet to the control system.

© SEW/Sienk

Standardization due to the multifunctionality of the decentralized drives is important for the special machine manufacturer precisely because the systems are usually one-offs: There are special-purpose machines where the customer's change requests are incorporated during commissioning, which can be taken into account thanks to the flexibility of the drives. The option of including the Movimot devices in the communication network via Profinet and connecting different digital sensors via the inputs and outputs available on board creates freedom. The machine builder can therefore add a drive to an existing installation, integrate sensors and other actuators and then try them out again.

Flexible security technology

The same applies to the integrated safety technology: Safe Torque Off (STO) comes as standard. The STO can be controlled via Profisafe using the CSB51A option card. The card is solely responsible for safely switching off the torque if the control system initiates an STO. This structure also creates the basis for switching safety areas as required via the existing physical Profinet bus without additional cable harnesses. The large number of complex individual systems in particular means that the special machine manufacturer is forced to act quickly and flexibly without the need for time-consuming wiring planning.

SEW-Eurodrive therefore offers integrated encoders to accompany the decentralized drive controllers within the Movi-C modular automation system, which simplify positioning tasks. Automatic motor commissioning via Movilink DDI, the digital data interface between motor and controller, also simplifies the process. The information from the electronic nameplate as well as braking and diagnostic data are transmitted. This simplifies and speeds up commissioning. This also applies to working with the control panel including pendulum operation.

Shuttle operation for retraction

Set up, put into operation, produce: The material flow is not quite that simple. All process modules have to run in first - over several hours or days. The roller conveyors alone run in for 24 hours at the special machine manufacturer, as the system first has to settle before any adjustments can be made.

What is comparatively easy to do for continuous tasks such as a roller conveyor drive means that a lifting application constantly moves up and down as it runs in. While a small PLC was previously required for the so-called shuttle operation, Rotte now uses an SEW hand-held control unit that has already prepared the shuttle operation. In the past, a programmer was needed for this, but today it can also be done by electricians or locksmiths. The manual control unit for Movimot therefore makes commissioning, including the retraction cycles, easier and faster.

The author: Andrea Balser is a specialist press officer at SEW-Eurodrive in Bruchsal.

© SEW-Eurodrive

Away from software and electronics and towards tangible mechanics: The fact that innovations do not necessarily have to be a question of digitalization becomes clear with the shaft seals. With a view to longevity, especially in 24/7 applications, Rotte relies on the new Premium Sine Seal shaft seals for its mechatronic drive units. The special shape of the sealing lip reduces wear on the contact surface with the shaft due to low operating temperatures. In combination with gear oils that are precisely matched to the respective gearbox and application in terms of their lubrication and cooling behavior, this increases the service life.

Easy modularization, continuous data flow

Decentralized drives, in conjunction with consistent Profinet communication, form the basis for a new way of working in machine and plant engineering. Task sections are easier to modularize, commission, dismantle and reassemble. The complete consistency of the data flow also makes it possible to optimize or retrofit systems without costly on-site visits.

Interview with Udo Marmann

Udo Marmann is Market Manager at SEW-Eurodrive in Bruchsal.

© SEW-Eurodrive

With 'Movimot', SEW-Eurodrive offers a decentralized drive unit that has been continuously further developed. Increasing networking and more intelligence in the device - what effects does this have on the drive and the inverter in particular?

Udo Marmann: Decentralized drive technology is the result of the basic philosophy of modularization and standardization of conveyor systems. An electric motor, a mechanical gearbox for torque conversion and an inverter for application-related speed control form a compact unit, often supplemented with sensors and safety elements.

We see the consistent interoperability between the individual drive units and the material flow coordination as a modern requirement in extensive factories or logistics centers. Consistently networked drive units in combination with powerful sensors, e.g. scanners or video systems for identifying and monitoring the conveyed goods, are becoming increasingly important. The information obtained about the usually heterogeneous conveyed goods, such as different sizes and masses, in the individual segments, combined with the appropriate software, enables dynamic adjustment of the conveying speed and utilization in the individual drive modules.

Keyword power density: At what point are there limits to miniaturization?

Marmann: The installation space and weight of a decentralized drive unit are mainly determined by the gearbox and the motor. Good manageability during installation and commissioning often determine the limits of the design. Today, the energy efficiency of drive solutions is increasingly becoming a decisive factor in system design. In recent years, the nominal efficiency of individual components has been regulated by legal guidelines, but the practical benefits that energy-efficient solutions can provide in real-life applications are also becoming increasingly important for manufacturers and users.

What does your roadmap for inverters look like, what further developments can we expect?

Marmann: The trend is clearly recognizable: the drive unit is developing from a 'simple muscle' into an intelligent, self-learning functional unit. In addition to its imaginary basic function of 'optimal conveying', it increasingly protects and supports people in its environment. Integrated functional safety enables safe and efficient working in order picking areas, for example.

Continuous measurement of load curves and environmental parameters, combined with agile data processing, enables well-founded statements to be made about the system status, identifies possible signs of wear and tear and provides early information about upcoming maintenance work. This functionality supports the operating personnel and avoids unplanned downtimes or unexpected failures. In short: reliability and plant availability increase measurably.