Module standard simplifies smart sensor design for the IIoT

Article By : Richard Quinnell

A new standard defines a small form-factor, microcontroller-agnostic module that can simplify the creation of smart sensors for the IIoT.

Industrial systems have utilized sensors and allied control systems for decades but turning those traditional sensors into smart devices suitable for networking together has always involved proprietary approaches. Now, the PCI Industrial Computer Manufacturer’s Group (PICMG) is releasing a module design standard that aims to make such systems more plug-and-play. Their new standard defines a small form-factor, microcontroller-agnostic module that can simplify the creation of smart sensors for an open computing network.

The PICMG Micro Sensor Adapter Module (MicroSAM) is a compact computing module developed to meet the needs of sensor-domain control within the industrial IoT (IIoT) application space. It specifically targets sensor connectivity, working within existing standards such as MicroTCA and CompactPCI Serial for the higher levels of control. The idea is to aid sensor vendors in creating smart sensor systems without having to develop or manufacture their own control circuitry or software. Instead, by purchasing such components from PICMG-compliant vendors, they will be able to make their systems interoperable with other suppliers and help speed the adoption of smart-sensor technology.

The module’s footprint is small, measuring 32×32 mm, and the circuit design targets low-power operation. The specification calls for power filtering and signal conditioning for embedded applications, an RS422 communications link, PWM output for motion control applications, and hardware trigger and interlock signals for system synchronization. It is intended to provide direct connectivity to a variety of sensor types, including analog voltage and current as well as digital devices, but is agnostic regarding which microcontroller powers the module. True to its industrial target, the module uses latching connectors to tolerate environmental vibration, and must handle temperatures from -40°C to +85°C.

In practice, the MicroSAM fits between standard, unconnected sensors and effectors and a bridge or aggregator device that connects multiple sensors into a network (Figure 1). The module’s purpose is to enable what are now non-IIoT devices to become IIoT-ready. The bridge device directly manages the sensor’s operation as well as formatting their data for transmission to a higher-level network.

MicroSAM module block diagramFigure 1 The MicroSAM module makes standard sensors IIoT-ready as part of a larger PICMG effort to facilitate IIoT adoption. Source: PICMG

The network model and data architecture that these modules work within are the subject of other PICMG standards currently under development. This work includes defining requirements for common firmware features, a common data model, the network architecture, and integration with the Distributed Management Task Force’s (DMTF) Redfish management API. The group’s overall goal is to accelerate the deployment of IIoT technology by addressing one of the impediments to wide adoption: a lack of standardization.

The aim is high, but only time will tell if it achieves the kind of adoption required to give the IIoT a significant boost. Standards do facilitate market growth, but only if there is a large enough market that those standards adequately address. Industrial applications are notorious for having enough unique demands on their solutions that proprietary systems can offer performance advantages that offset the savings in time and effort that come with standardized approaches.

This article was originally published on EDN.

Rich Quinnell is a retired engineer and writer, and former Editor-in-Chief at EDN.

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