Opportunities and Limitations of Industrial Internet of Things for Small Motor Drives

Mark Lewis, VP Sales & Marketing • Dart Controls, Inc.

The Internet of Things (IoT) is generating a lot of buzz.  Basically, the IoT concept is to add ‘smarts’ to a device for the purpose of getting it connected to the internet.  Once connected the benefit is the ability to monitor or control it.  The Industrial Internet of Things (IIoT) is a more specific application of the concept, most often thought of in a factory setting.  Factory automation has been advancing for decades, dramatically in recent years.  IIoT is enabled by adding sensors generously throughout a facility to directly measure and communicate information that may previously have been estimated, calculated, or not measured at all.  The goal of course is to do (whatever it is) better, faster, and more efficiently.

Factories use a lot of motors, and motors are often paired with a ‘drive’, AC or DC depending on the motor.  Big motors use big drives, often priced in the five and even six figure range.  These big drives often have a lot of ‘smarts’ just to control the motor, the incumbent ‘smarts’ also enable the ability to connect to a network and thus offer communication via the Internet.

But what about a small drive that costs under $100, controlling a fractional horsepower motor?  What are the opportunities (and roadblocks) to including these devices in an IIoT environment?  We will explore this issue, and current expectations for the future.

Traditional Factory Infrastructure
DIOT2The traditional factory network is separated into two parts – the Operations LAN and the Control LAN.  Data is freely shared between the two, but their purpose and characteristics are different:

Operations LAN: High speed (up to Gigabit), non-deterministic, susceptible to noise interference, more expensive physical media, multi-purpose, more open.

Control LAN: Moderate speed, deterministic, noise protected, less expensive physical media, dedicated purpose, limited access

The Operations LAN, having many jobs, needs to be open and accessible and run at high speeds to handle the amount of traffic on the network.  However, these communications are not ‘mission critical’ so data collisions may occur (non-deterministic).  The physical media (wiring, cables) are not generally in high electrical noise environments, but do involve more cost (commercial grade e-net switches, routers and hubs) compared to Control LAN wiring which can be as simple as a twisted pair of wires.

A Control LAN will sacrifice speed to gain certainty of data communication (deterministic).  The processes under control do not need more speed, so level of control is not compromised.  The Control LAN is focused in purpose, to operate the factory safely, securely and efficiently.  Protections against electrical noise are a must, as the environment may include heavy equipment and electrical switching.  Human Machine Interface (HMI)/ operator interface with the Control LAN is limited to need, based upon job function.

With this background, the challenge of implementing IIot is merging these two distinct environments together.  In addition, companies will be loath to decommission the trillions of dollars’ worth of hardware and software currently in use.  It may be realistic to expect a more gradual change, an evolution to occur.

This diagram shows an example of how an IIoT enabled factory infrastructure could be implemented today WHILE preserving the investment in existing control products.

This diagram shows an example of how an IIoT enabled factory infrastructure could be implemented today while preserving the investment in existing control products.

Small Drive in IIoT Application
Most factories employ some sort of supervisory controller / plc / HMI, or some combination thereof.  These devices typically offer at least one Ethernet port and one serial communication port (Modbus shown).  In this scenario, small drives could be added via Gateway or directly to the Control LAN at minimal cost.  The data from these small drives would be accessible via their supervisory controllers to the Operations LAN, already connected to the Cloud / remote access / web portal / smart phone app.  Specific chip sets are being developed by suppliers to support this Gateway function in a single integrated circuit.  Over time and as control devices are further developed, Ethernet support is likely to be offered in even small drives, which in this scenario would be connected directly to the Operations LAN.  This would be the most probable evolutionary path taken at the factory level previously mentioned.

Another Thought
There are benefits to be realized today with a networked small drive within an OEM piece of equipment. The same concepts mentioned before for a factory could apply to a single piece of OEM equipment with multiple devices employed.  This is an example of an OEM conveyor belt oven with 11 devices connected by a single twisted pair of wires, daisy-chained from device to device.  The HMI Ethernet port is used from remote internet access to troubleshoot, collect data, manage (software) updates and anticipate preventative maintenance.  The advantages to using IIoT concepts inside a single piece of DIOT4equipment include savings in wiring labor and materials, consistency of product output, remote troubleshooting, and the ability to add services such as automatic raw material stock replenishment.

Predictions for IIoT in 2017
As offered by Stephen Mraz in the December 2016 issue of Machine Design, here are the Top Predictions for IIoT in 2017:

  • IIot gets ‘smarter’ – more computing power, more IIoT specific products developed
  • Data collection moves to cloud – purpose built collection services as opposed to dumping everything into a SQL database
  • Recruiting IIoT-capable employees remains a challenge
  • Development of common-sense IIoT products – more than just ‘connected’
  • IIoT market will expand despite security risks – proving the need and value (not detailed earlier, but a big challenge at the Control LAN level is the need to be more open and accessible – a security concern)
  • Successful IIoT solutions will include services – for successful launch
  • Startups will gain ground – especially as market matures.  Expect both product and service suppliers keen to IIoT market needs to emerge
  • Standards remain ‘TBD’ – suppliers are still in discovery mode and not yet ready to commit to specific standards (However, significant work has already begun in the area of Security mentioned previously)

Conclusions
IIoT is going to happen, over time.  The perfectly functional (large!) installed base of factory controls and sensors, as they are retired, will be replaced with network capable improved products – developed with IIoT in mind.  Security issues will be addressed sufficient to support ubiquitous access from within and without the plant / machine employing an IIoT design.  Expect a flurry of products and service providers to emerge that have been developed with IIoT specifically in mind.

 

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