Bringing IoT to the sensor domain: Sensors Expo recap
Sensors Expo was held in San Jose from June 26 to 28, 2018. It was great to see a trade show with growing attendance and enthusiasm. Regardless of the type of sensor vendor on display, the trend to connect sensor technologies was widespread. Featured were wireless innovations, an embedded system area, a university showcase, and even clever end solutions such as the sensor-laden mattress, which we all admired longingly after being on our feet all day.
From an embedded computing perspective, there seemed to be two pressing needs in the sensors market: First, a way to connect legacy sensors so that they can be used in modern and future systems. Second, for those IP-enabled sensors that are “connected,” the question becomes how they will interoperate with devices from other vendors. Of course there are a wealth of great proprietary, closed sensor solutions. However, they would face serious challenges in connecting with other devices on the factory floor or other IIoT [industrial Internet of Things] applications. This is where PICMG’s new IIoT specification concept comes in.
The PICMG approach is to create a metadata model – a master schema, if you will – of all types of individual companies’ data models to work with other devices. This metadata model will allow all types of sensors – those that measure pressure, temperature, color, proximity, etc. – to interface in a well-known language of the IT room. The models will also include multipoint sensors, controllers, and some specialty function devices. PICMG has a working agreement with DMTF [the Distributed Management Task Force, an industry-standards organization] and will use its Redfish API.
PICMG had a proof-of-concept demo at the Expo showing a basic machine with three 8-bit servo controllers that adjusted the machine’s X, Y, and Z axes. Each controller used the PICMG data model providing basic PUT and GET commands based upon RESTful interfaces. By showing an IIoT implementation over an established and well-known IT format, visitors were able to imagine a connected approach using their own product/solution. Sensor companies understood that it was advantageous for them to be an active participant to ensure their schema approach is incorporated into the PICMG metadata model.
IIoT sensors present themselves as intelligent, managed devices over the factory network using the common metadata model. Using RESTful application programming interfaces, sensors may be monitored and controlled using standard IT methodologies. For sensors and actuators that must respond in real time, it may be necessary to place a controller close to devices in order to monitor the devices locally. This arrangement reduces the latency and improves determinism over having the devices remotely controlled through the factory control center. These local IIoT controllers would present the connected sensor data models to the upstream control center. They would also introduce programmable “listener” functions that implement local policies when sensor events occur. The listener functions may also be directly implemented in sensors and actuators.
Legacy sensors can be addressed as well with connections to the IIoT control center. Initially, programmable logic controllers (PLCs) can be connected over their existing interfaces and be managed through legacy software. As an intermediate step to full IIoT functionality, the PLC can later be replaced by an IIoT control gateway. This device “translates” the sensor’s native protocols to a RESTful data interface using the common metadata model. This approach allows the same sensors to be used while the control architecture is migrated to IIoT technologies.
PICMG is planning a specification for a small (postage-stamp-sized) interface so that legacy sensors can be connected and interface with other IIoT devices. At a later stage, the older sensors can be replaced with fully IIoT-enabled sensors.
PICMG is known in the industrial automation world mainly for hardware specifications such as cPCI Serial, COM Express, and CompactPCI. However, the specification development organization is also well versed in software/firmware. For the TCA [Telecom Computing Architecture] designs, PICMG developed the Hardware Platform Management spec that enabled system performance monitoring, predictive maintenance, software upgrades in live systems, event logging, and more. Leveraging its expertise in software/firmware specifications – combined with the vast implementation of PICMG-based hardware from its member companies – PICMG believes that it is in a strong position for a true plug-and-play IIoT specification.