Targeted monitoring, influencing and evaluation of production processes with ERP systems (Enterprise Resource Planning) and MES (Manufacturing Execution Systems) is currently state of the art. The benefits lie in efficiency and quality improvements in production and also enable the economical manufacture of customer-specific products, even in small batch sizes down to individual items. The targeted evaluation of relevant machine data leads to further cost savings through targeted preventive maintenance. Newly planned systems (greenfield) already have smart sensors and actuators and often provide real-time access to internal values and system statuses. This is rarely the case with older existing systems. Retrofitting with suitable additional sensors and actuators can solve these challenges in most cases. The problem here is the integration of the sensors, particularly over longer distances.

Sensors do not speak IT

The Microserver: a smart communication module with dimensions of 13 mm × 16.7 mm × 3.8 mm, consisting of an ARM Cortex R4 system-on-chip with watchdog, flash memory, network and peripheral interface and integrated 24 V power supply.

© Perinet

Even though the range of smart sensors on offer is constantly growing, it is still quite limited and expensive. In addition, they often have to be configured and maintained by different manufacturers using a wide variety of often proprietary tools. A direct connection via buses is complex and generally does not allow large distances to or between the sensors. In addition, bus solutions require expensive and complex gateways for protocol and level conversion. This heterogeneity results in high installation and maintenance costs. However, the actual goal is and remains seamless direct communication from the outermost edge of the network, the field level with its sensors and actuators, right up to the top level in IT without the need for additional gateways. Perinet has developed a technology for this purpose: special micro-servers that can convert and communicate local sensor data into standardized data records that can be processed directly by IT. Since IT has been relying on Internet Protocol (IP)-based networking and communication for years, it was obvious that the entire external communication of these micro-servers should also be handled via the Internet Protocol and the data layer above it in accordance with the OSI model.

SPE as the new networking standard

The aim of the microserver: seamless direct communication between the field level and its sensors and actuators, right up to the top level of IT without the need for additional gateways.

© Perinet

Originally coming from automotive technology, SPE is also establishing itself in industrial automation as a cost-effective and literally flexible standard for high-performance networking at field level. Like conventional Ethernet, it uses the IP protocol and is therefore directly IT-compatible. Another major advantage of SPE is that existing, unshielded Cat5 connections or twisted wire pairs (bell wire) can also be used for wiring. Far beyond the (automotive) specification, maximum segment lengths of up to 300 m (Cat5) or up to around 100 m (with bell wire) are possible in practice for connections with 100Base-T1! In contrast to classic Ethernet with two or four wire pairs and complex shielding, SPE enables simple and cost-effective installation with just one wire pair and significantly smaller bending radii. Virtually any topology - including star and point-to-multipoint with long spur lines using switches - can be implemented if the hybrid SPE variant with an additional wire pair is selected. If required, this additional wire pair enables the electrically isolated, interference-free supply of additional electronics with up to 400 W as well as plug-and-play with the ready-to-connect cable components from Perinet. By choosing the 100BASE-T1 variant of SPE, multi-channel video-capable data rates of up to 100 Mbit/s are also possible in the field. SPE therefore represents a high-performance, standardized and therefore future-proof solution for both old and new networks.

The microserver and the low-code configuration

The task of the microserver is to handle all communication between the cloud or IT connected via Single Pair Ethernet and the respective sensor or actuator. It is integrated into a smart communication module consisting of an ARM Cortex R4 system-on-chip (SOC) with watchdog, flash memory, network and peripheral interface and integrated 24 V power supply unit. In this case, smart means that the SoC not only converts levels and protocols, but also provides the integrated microserver and many other intelligent functions. It can pre-process and consolidate sensor signals and convert them into digital data records that can be used directly by IT. Thanks to the option of local intermediate storage, the data can be communicated directly, time-controlled or event-controlled as required.

The microserver is embedded in a 4-pin SPE M8 round connector.

© Perinet

The module is available in two different designs: On the one hand as a SOC board with dimensions of only (13 × 16.7 × 3.8) mm³ or embedded in a 4-pin SPE M8 round connector or adapter. Different adapter versions are available to suit the respective sensor connections: with 4-pin M12 sensor plug (A-coded) for Pt100 sensors, with 4-pin M12 sensor plug (A-coded) for 0-10 V voltage interfaces or with 4 connection cables for GPIO interfaces. The modules can be accessed and configured via the SPE connection using any web browser.

Configuration through low code

In most cases, a simple configuration of existing elements and functions is sufficient for customization. The complete network functionality, firmware management and all security functions from certificate management to 256-bit end-to-end encryption are pre-configured and can be put into operation immediately in just a few steps. Additional functions enable adaptation to system conditions as well as evaluation and consolidation of the respective sensor data. In this way, a simple sensor can be turned into a smart sensor system with minimal effort (low-code). For more specific or more extensive adaptations, the modules can be expanded with their own electronics on the hardware side. On the software side, a completely ready-made development environment with debugger, extensive board support packages and reference implementations support the development.

Encryption solution with PKI

The author: Dr. Karsten Walther is Managing Director at Perinet.

© Perinet

With the increasing convergence of OT and IT, the importance of cyber security is also growing. In addition to inadequately secured remote maintenance access, openly accessible lines to external sensors and unsecured fieldbuses pose a high risk of attack. While a wide range of protective measures can be taken for new installations, this can be difficult for old systems. When Perinet technology is used, the signal is already securely encrypted from the sensor and therefore protected. The user-ready, pre-configured public key infrastructure (PKI) security solution PKI2go enables highly secure communication between all services and users of an IoT application. This makes it easy to implement zero-trust solutions that work locally and independently of the respective network setup. The fact that the sensor manufacturer, integrator or system operator only has to worry about their own application is essential for estimating the effort and costs involved. The operating system, including the local web server and the complete security infrastructure, is supplied and maintained by Perinet ready for operation.