Motors, Drives

Industrial drive specification criteria for success

The key to selecting an industrial drive is to understand how that drive has been designed and constructed to operate in conjunction with other machines and control systems.
By Paul Streatfield August 16, 2019
Courtesy: CFE Media

Continually updating specification choices, in line with the rapidly evolving landscape of Industrie 4.0, can be a challenge. However, in doing so, machinery manufacturers can offer their customers a wealth of financial benefits as well as better use of factory space, optimized machinery performance and improved safety standards.

The key to selecting an industrial drive compatible with autonomy is to understand how that drive has been designed and constructed to operate in conjunction with other machines and control systems. In doing so, specifiers can better establish whether the drive will deliver tangible results, and whether the investment will stand the test of time against the ongoing evolution of connectivity in the industrial sector.

Cabinet-free drive technology

Intelligent servo drives have become an indispensable element of modern machines. End users have enjoyed efficient format changeovers and motion profile adaptations at the push of a button. However, this performance-enhancing technology does come at a cost, and with more servo drives comes the need for larger, space-hungry, control cabinets.

These cabinets can essentially fill production space which would be better used for expanding a production facility through modularization. Historically, the motor and control unit have been separated from each other with a power and encoder cable running from each motor into the control cabinet. This had been the only way to utilize servo technology until 2014 with the introduction of cabinet-free drive technology, which retains all the advantages of servo drives, but delivers up to 90% lower cabling costs and a significant gain in space by eliminating control cabinets entirely.

Designed in accordance with IP65, all network access components previously located in the control cabinet can now be installed directly into the machine. The mains module is a single unit and connects the entire system to the mains, containing the mains filter, the mains choke and the mains contactor. The regenerative supply module with control electronics, braking resistor and braking transistor completely replaces the supply and control electronics in the control cabinet, allowing the traditional cabinet structure to be completely removed from the system design.

Compared to traditional automation, cabinet free solutions use just a fraction of hybrid cabling with the same motor spacing. This cuts material costs and installation times, and also reduces the probability of faults in the cabling and delivers additional monetary savings through the direct connection of sensors, input outputs (I/Os) and Fieldbus components to the decentralized drives.

Safety features

Drive-integrated safety functions can offer an economical method of ensuring maximum protection for people and machines while increasing productivity ergonomics and efficiency in engineering.

It is no secret that uncontrolled movements pose a significant hazard and the more time operators have to spend inside a machine, the longer manufacturers are spending ensuring compliance with the highly stringent safety regulations outlined in the Machinery Directive 2006/42/EG or the relevant regional standards.

Intelligent, drive-integrated safety functions make it easier and more efficient to perform maintenance work in accordance with legal requirements, offering a wealth of competitive advantages when it comes to reducing system downtime and labour costs.

Building on the in-demand integrated safety functions such as safe stop 1, safe limited speed and safe direction of rotation, drive-integrated safety features are already offering a wider range of logic functions designed to deliver maximum machine safety even satisfying the highest safety level Category 4, Performance Level e and SIL3, in some instances.

Some of the more sophisticated functions available include safe door locking and safe braking and holding systems capable of monitoring and controlling two independent brakes via redundant channels in the drive, ensuring safety in the event that operatives need to spend time beneath gravity-loaded axes.

Operational flexibility

Open core engineering puts new application possibilities within reach for the very first time, replacing traditional human-machine interface (HMI) devices with smart alternatives during the commissioning, operation and diagnostic phases. It expands access to the control core and invites the use of mobile and digital technologies into the industrial environment.

Applications made possible with open core engineering are said to include commissioning machinery with scannable QR codes and the visualization of processes within the machine, plus diagnostic tools which allow obtained data to be transmitted immediately for storage and evaluation. With new and extensive applications available using commonly used high level languages across all standard operating systems, developing bespoke solutions to a range of complex machining requirements is far more possible than ever before, making open core engineering a key specification criteria for drives moving forwards.

Eliminating higher-level controllers

Some drive solutions combine motion and common programmable logic controller (PLC) functionality to create a modern, open automation platform for modular machine concepts.

By decentralizing the control architecture in a compact motion control system – with both motion and logic control handled directly in the drive – it is possible to completely eliminate the need for higher-level controllers. As well as offering financial benefits due to less hardware and cabling, this type of drive architecture also enables easier engineering, faster startup, faster diagnostics and the added benefit of only having to back up one data source.

Scalable for a variety of process and manufacturing facilities, with ready-to-use function libraries to simplify use, this style of drive-based solution is available as a single axis control for basic applications as well as a multi-axis control for applications with a maximum of ten axes.

This article originally appeared on the Control Engineering Europe website. Edited by Chris Vavra, production editor, Control Engineering, CFE Media, cvavra@cfemedia.com.


Paul Streatfield
Author Bio: Paul Streatfield is strategic product manager at Bosch Rexroth.