Written by Dan Burbridge, Graduate Engineer at Siemens UK

What is MICRO-DRIVE?

SIMATIC MICRO-DRIVE is Siemens’ first entry into the extra-low voltage DC drive space ranging from 100W to 1000W with full failsafe variants. Building upon the SIMATIC brand it integrates seamlessly into the Totally Integrated Automation environment and therefore benefits from quick and easy programming and commissioning in the TIA Portal. It’s sister product the F-TM servo drive is part of the ET200SP architecture. It provides DC drive capability at 280W including basic safety features. The Micro-Drive delivers on high speed, high precision positioning tasks in production and manufacturing as well as in innovative applications.

Entering the Healthcare Market

Servo Motor Applications in the Healthcare industry:

  • MRI Tables
  • Ceiling mounted radiography systems
  • Laboratory Equipment
  • Patient Lifting
  • Dosing Pumps
  • Portable Equipment
  • Medical AGVs

For motion control products, especially those designed for use in industry, the healthcare market introduces a unique set of challenges. First and foremost, environment. Applications generally sit in collaborative environments, with people working in close proximity to the equipment and in some cases even being moved around by it. This naturally imposes some stringent safety requirements. Furthermore, in those environments noise emissions, both audible and electrical noise must be reduced to increase user experience and limit interruption to nearby sensitive medical equipment respectively. The task itself of moving patients or imaging equipment also has strong requirements on smooth operation and high precision positioning. For MRI tables, ceiling mounted systems, and portable equipment there are some constraints on space and power, so a system must be compact, operate from a single-phase power supply, and for battery applications such as portable equipment, low power consumption. All of these constraints need to be met in conjunction with the final constraint of downward pressure from insurance companies and government on price.

How does Micro-Drive Meet These Requirements and add Business and Customer Value?

At this stage it is worth dividing the constraints into some subsections: safety, noise, versatility, and positioning.

Safety Integrated

    The concept of Safety Integrated is to take safety functionality that would previously require external sensors and bring that capability into the drive itself. Micro-Drive embodies this principle. It includes complex safety functions including Safe Torque Off (STO), Safe Stop One (SS1), Safety Limited Speed (SLS), Safe Speed Monitoring (SSM) and all new Safety Limited Torque (SLT). SLT is completely new to the SIMATIC/SINAMIC portfolio and adds value by removing the need for expensive sensors for collision detection and can be set at four levels. The example provided in the picture below shows how SLT could be implemented for four different levels for four different loads making the system versatile without compromising in safety. Now imagine the loads are people of different weight being lifted by an MRI table and the value becomes clear. Safety functions are controlled via PROFISAFE from any of Siemens full range of safety PLCs. Safety integrated has the added benefit of reducing cost of purchasing and configuring sensors. This safety functionality and cost reduction implications meet requirements for medical applications in collaborative environments.

Noise

Micro -Drive is low noise in both senses of the word. Firstly, audible, DC brushless motors are nearly silent which, for applications such as MRI tables, improves customer experience considerably as well as making it suitable for collaborative environments. Secondly, electrical: Sensitive electronics such as those used in medical imaging may be susceptible to electrical noise from AC devices. Using a DC drive such as Micro-Drive avoids this.

Versatile

To meet the stringent requirements of the medical industry, the Micro-Drive needs to be versatile. The Micro-Drive system flexibly combines system components including myriad DC brushless motors suitable for a wide variety of medical applications. Not only does Micro-Drive use power efficiently, it also regenerates its own. For battery applications, the lack of DC/AC conversion and compatibility with efficient DC brushless motors means that system losses are small when compared to an AC equivalent drive system and reduces overall system cost. Furthermore, disabling the break chopper means that the Micro-Drive can actively regenerate energy during breaking. The Micro-Drive is compact with a width of just 50mm for the 100W variant and 90mm for the 1000W variant. The TM-Servo drive fits into the ET200SP platform and therefore delivers 280W of power in a footprint just 20mm wide. This small form factor for both drive types makes the Micro-Drive system truly versatile and suitable to meet the power and size requirements of the medical industry.

Positioning

Micro-Drive utilises servo drive technology and benefits from sophisticated yet simple motion programming in the TIA Portal. Servo drives are famed for high resolution positioning at relatively high speed and the tight control provided by SIMATIC controllers allows for smooth acceleration and motion paths to meet customer comfort requirements. As with all the capabilities we’ve seen so far, this functionality is easy to configure with a Micro-Drive specific ‘single button tuning’ capability in TIA Portal. This automatically detects load characteristics and tunes the drive accordingly. With just a single button press! 

Solution fit for the future

The characteristics of Micro-Drive make it fit for future developments in the medical industry particularly in the Autonomous Guided Vehicle (AGV) sector. AGVs are a considerable growth market globally with a market value of USD 4.55 billion in 2019 and is projected to reach USD 11.70 billion by 2025[1]. AGVs are exciting prospects for hospitals. Unlike humans they do not spread bacteria, require a wage, or suffer from fatigue. This places them as prime candidates for all hospital logistics tasks including transporting waste, linen, sterilised devices and much more to their intended destinations. In the UK we are already seeing them adopted by the NHS, notably in North Bristol where AGVs operate freely in staff areas to transport linen, food supplies, sterile instruments, and pharmacy items[2]. Micro-Drive is in a prime place for the AGV market for many of the same reasons outlined above. AGVs are battery powered, compact, versatile, require high safety standards, and close control and positioning capability – Micro-Drive is the obvious choice.

If you need more information on how the MICRO-DRIVE could help your business, send an email to our team for help with any requests, or head straight to our shop for the full range of MICRO-DRIVE products.

EMAIL OUR TEAM   SHOP FOR MICRO-DRIVE

[1] https://www.mordorintelligence.com/industry-reports/automated-guided-vehicles-market-industry

[2] https://www.nbt.nhs.uk/about-us/building-brunel/automated-guided-vehicle-system

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