Industrial IoT Overview

The Need

Why is PICMG creating an Industrial Internet of Things (IIoT) specification effort?  Aren’t there dozens of IIoT efforts already out there? This is not an uncommon question we have faced.  But as PICMG’s IIoT push has expanded from the exploratory phase in mid-2017 to a complete smart sensor demo in 2021, the excitement for our concept has grown rapidly. The PICMG IIoT effort is centered around creating plug-and-play interoperability in the sensor domain, essentially to the “last foot” of the network. While other efforts focus on communications protocols, standardized gateways, etc, the PICMG approach allows for systemic detection and control of sensors and control points in a very simple, reliable, and easy-to-use human readable format .

Developing an interoperable IIoT specification is a natural fit for PICMG. The embedded computing specification development organization has over 20 years of in-depth knowledge of the industrial computing market. At PICMG we seek to accelerate the adoption of IIoT in the markets we serve by providing meaningful open specifications and design guides to aid our member companies in creating high-quality, interoperable computing solutions. We are doing this by leveraging our historic strengths in industrial computing, expanding our community of practice to embrace a wider audience of IoT developers, and building partnerships with other IIoT-focused standards organizations.

PICMG Approach

As mentioned, the PICMG approach focuses on plug-and-play interoperability of the sensor domain. This encompasses a large installed base of non-IoT (not IP-enabled) products and new IoT-enabled smart sensors. To achieve this, we need a mechanism for connecting non-enabled devices. Second, we need a way for them to interact reliably and securely with each other, and third, we need a means for all of them to be controlled simultaneously in a human usable way. In order to achieve this, we have developed a family of three IoT specifications that meet each of these goals specifically.

In a smart factory, there are multiple layers of firmware, software, and hardware interacting with each other to produce products.

At the lowest level are the physical sensors and actuators of the factory equipment. Each of these devices may or may not be IoT-enabled, so hardware is needed to allow these devices to interoperate. To address this issue, PICMG developed IoT.0 – MicroSAM.

MicroSAM is the first specification that PICMG developed for IIoT, and it solves the problem of enabling non IoT devices. Ratified in October 2020, this 32mm by 32mm low power micro-controller board is designed to allow for non IIoT-enabled devices to interact with an IIoT gateway in a plug-and-play manner, regardless of their type.

In order to make this hardware function properly, firmware is needed to allow the devices to self-describe themselves and communicate with other devices. The newest specification that PICMG has created is the IoT.1 Firmware specification, which acts as the software schema for interoperability. The PICMG IoT.1 specification enables all of these sensors and actuators to self-describe themselves. There are all types of sensors on the factory floor – pressure, temperature, inductance, capacitance, etc. Taking temperature for example, these sensors would need to provide their manufacturer/product ID, temperature range, measurement scale (F or C), etc. Some sensors could have accuracy ranges of (for example):

                  • +2 to -3 degrees C
                  • +1 to -1 degrees C
                  • +20 to -10 degrees C

Starting with #2, the postage-stamp size board would interface to non IIoT-enabled sensor devices to make them IIoT-enabled. This small, low power micro-controller board would have a couple of ubiquitous connection ports such as Ethernet, USB, etc. Assuming sponsorship in PICMG is active in this area, a target goal date for availability would be Q2 2019.

The IIoT Data Model is the software schema for interoperability. The PICMG IIoT specification will enable all of these sensors and actuators to self-describe themselves. There are all types of sensors on the factory floor – pressure, temperature, inductance, capacitance, etc. Taking temperature for example, these sensors would provide their manufacturer/product ID, temperature range, measurement scale (F or C), etc. Some sensors could have temperature ranges of (for example):

                  • -40 to 15 degrees C
                  • -20 to 30 degrees C
                  • -0 to 70 degrees C

The PICMG IoT.1 specification defines a data model that in this case covers plusAccuracy and minusAccuracy. When a “GET” command is sent to each sensor for minusAccuracy, the responses they would provide would be minusAccuracy=3, minusAccuracy=1, and minusAccuracy=10 respectively. The sensors are self-reporting their capabilities for true plug-and-play.

In short, what is happening in this example is the IIoT-enabled sensors are interfacing with the computer software. The software interrogates the new hardware to determine what it is, and what its resource needs are. The hardware, in turn, responds with information that describes itself in a manner that the computer hardware understands. The information describing the hardware can be thought of as a “data model” – a description of the hardware, its needs, and capabilities.

The data model also forms the interface by which the device behavior can be altered. By writing a modified data model back to the device, the device behavior is updated with the new changes For instance, a thermostat data model might contain a field that specifies the temperature setpoint at which the air conditioning unit should turn on. Writing back to this field with new information would signal the thermostat to change the setpoint to the new value. In order to do this effectively, PICMG IoT.1 focuses on making sure that any field is easily human readable. The data from the sensors and actuators is typically analog, while the software needs to be able to interpret binary code. Neither of these are easily readable, so IoT.1provides data in the human readable TCP/IP data format in order to facilitate easily understandable command sets. This process was made simpler by working with the DMTF to use the MCTP and PLDM data transfer protocols to facilitate the communication between the MicroSAM and smart system.

The final step in creating a complete IIoT system is having a mechanism that allows the isolated sets of smart devices in a factory machine to be run by a machine controller, which is in turn run by a factory assembly line controller. To do this, a network architecture is needed, along with another data model to manage the information being used. In fact, PICMG has formed a strategic alliance with the DMTF organization to utilize RedFish® APIs as the next step in the IIoT effort. RedFish is a RESTful interface for the remote management of a platform. RESTful stands for Representational State Transfer. REST is important as it is very simple, well-established, and easily facilitates the interaction of clients and servers.

RedFish Framework Advantages:

  • Very easy for humans to use and for machines to parse and generate
  • Highly scalable
  • Re-uses existing principles in well-structured formats
  • Secure, interoperable, and extensible

The RedFish interface definition includes JSON primarily, ODATA, etc. It leverages common Internet and web services standards to expose information directly to the modern tool chain RedFish has profiles for required elements such as server, storage, network, telco, rack/power, and the overall hardware management. The hardware management concept is very similar to PICMG’s Hardware Platform Management (HPM). By utilizing a very well-known coding structure in the IT world, PICMG has an excellent framework upon which to build our RedFish communication protocol. While RedFish is an excellent start, we’ll need to build upon its structure for the effort. We’ll need to add capabilities for motion control to the framework, including likely multi-cast capability and clocking (NTP – Network Time Protocol), etc. Other areas such as Security are also extremely important and will be addressed. See the Grand Challenges for IIoT for more detail.

Taking the RedFish API Framework, we can extend the schema structure to one for a machine controller. Here is an example:

Below is an example of a demo platform that PICMG created to illustrate our IIoT concept.  It consists of a controller board (COM Express for example) with multiple micro-servers that can control various aspects of the machine. A few examples are x-axis, y-axis, z-axis, etc. We showed that by logging in to the RedFish API interface, we could set values via the simple “GET, PUT” schema instructions to manipulate the CNC machine remotely.

The Smart Factory Imagined

With an interoperable PICMG plug-and-play IIoT specification in place, one can imagine how the smart factory floor may look in the near future. There could be localized COM Express or other IIoT Control Gateways and/or an IIoT Controller based on the COM Express versatile mezzanine approach or a multi-slot chassis based on cPCI Serial, MicroTCA, or a proprietary form factor.   Legacy PLCs and sensor points could have the postage-stamp “adapters” that enable the IIoT interface. PICMG member companies and those who utilize the specification could employ their “secret sauce” on top of the open, modular, and scalable platforms. This may be specialized software for the applications, extra security provisions, I/O interfaces, and countless other ways to differentiate. See Figure 4 below for a model of the potential factory floor.

Join the Effort

The PICMG IIoT effort is underway, but it’s not too late to participate. Members will be given the option to join the subcommittee. PICMG is also working with the greater IIoT community at large to bring in experts and leverage existing work. Who should join:

  • Sensor product vendors
  • Embedded computing product vendors
  • Industrial IoT industry leaders and experts
  • Existing PICMG members and users of the specification
  • Leading end-users, smart factory integrators
  • Research, academia, or other experts

If you are not yet a member of PICMG and have an interest in participating, please contact us at [email protected].