Simplified remote access
Remote monitoring and control systems using modern data collection techniques deliver improved performance and security, along with simpler implementation and lower costs
By Benson Hougland
Data collection from industrial facilities and plants provides a number of benefits to end users, system integrators, and machine and process skid builders. End users can monitor their facilities and plants worldwide from any location with cellular network or Internet access, and system integrators can do the same for their projects. Original equipment manufacturer (OEM) machine and process skid builders can monitor their products and systems wherever they are installed, even at remote customer sites.
Data collection by OEMs can be especially useful for both the OEM and the customer. Data can be acquired for analysis and remote monitoring, and data can be sent to machines and process skids for remote control. This two-way remote access provides:
- remote monitoring to quickly alarm and alert personnel
- predictive capabilities to anticipate problems before they occur
- remote control to respond to issues and problems
- improved overall equipment effectiveness: better uptime, throughput, and quality
- cost savings by eliminating most trips to the field
In addition, OEMs can:
- log usage data for billing or maintenance
- gain insight into customer needs
- analyze data to improve future product or process designs
Although most OEMs need remote access to provide the quality of service their customers want, the barriers are high and include security issues, technical difficulties, and costs.
Cybersecurity is a major concern for both OEMs and their customers. Busy information technology (IT) departments may not have the time, resources, or technical skills to set up remote access to automation systems and equipment.
As a result, older methods like opening ports through firewalls and creating virtual private network (VPN) tunnels are falling out of favor. Newer methods of remote access, particularly those using the Message Queuing Telemetry Transport (MQTT) protocol in publish/subscribe communication models, can be a major improvement, providing the data and access OEMs need without burdening their customers (sidebar).
Industrial hardened edge programmable industrial controllers (EPICs) address these and other remote access requirements with local computing, multiple programming options, local control, and sensor input and output interfaces.
Edge processing encompasses at least three functions. The first is to collect, process, view, and exchange data where it is produced-at the edge of a network. This function requires a powerful processor and an open operating system, such as Linux. The processor filters out anomalies, sorts relevant data, and creates exception-only reporting.
The second function is securely storing and sharing data among databases, cloud platforms, Web services, and programmable logic controllers (PLCs) using modern communication methods. Sharing data with this wide range of hardware and software requires support for multiple communication options at both the hardware and software level.
At the hardware level, multiple communication ports are a must. Minimum requirements for modern systems include multiple gigabit Ethernet, USB, and serial ports. At the software or protocol level, many protocols should be supported, including different variants of Ethernet, Modbus RTU and Modbus/TCP, and MQTT.
Many industry offerings now include embedded support for multiple connectivity methods in their EPICs, including Ethernet and Modbus protocols, plus OPC UA drivers and MQTT/Sparkplug. These methods give support now, and also provide for the future, as vendors are constantly updating their protocol support options.
The third function of an edge processor is to bring data visibility to authorized personnel in several ways: on an integral touchscreen, on a local human-machine interface (HMI), and from any device capable of hosting a Web browser (figure 1). Many OEMs will find an integral touchscreen, and an HDMI port for optional connection to an external display, a significant benefit.
If the touchscreen is sufficient, then the OEM can save the expense of purchasing and installing an external HMI. If the vendor includes an HMI development tool as part of the EPIC software package, a low-cost graphics monitor can simply be connected to the HDMI port to provide an external HMI. In that case, there is no need for an external PC-based HMI, which is very expensive due to the high costs of industrial PCs and PC-based HMI software.
Figure 1. Local monitoring, control, and adjustments are greatly facilitated by providing built-in HMI on the edge controller.
Multiple programming options are required for any modern EPIC. Some of the more popular languages are flowcharting with scripting options for sequential machine and process skid control, and the suite of IEC 61131 languages. These two options will be sufficient to support most real-time control needs, but some OEMs may require or prefer more flexible and powerful programming languages, such as C/C++, Python, and Java. These and other languages can be most easily used if the EPIC provides secure shell access, a common feature when a Linux operating system is used. And all of these languages can be used together, with data passing among them internally within the EPIC as required.
For many remote access applications, real-time control is of secondary importance, with data exchange among various controller, HMI, and other platforms the primary goal. For these types of tasks, the browser-based, open-source, flow programming tool Node-RED (https://nodered.org) is becoming more widely used by EPIC vendors, and by many other companies in both the commercial and industrial sectors (figure 2).
Using this open-source visual language, developers can cut and paste prebuilt function blocks or nodes to configure various communication paths. Because Node-RED is specifically designed for these types of tasks, it is much easier to use for data handling than languages designed for real-time control, such as flowcharts, or general-purpose languages, such as C/C++, Python, or Java.
Figure 2. The open-source Node-RED programming tool embedded in edge controllers enables users to easily wire together hardware devices, APIs, and online services.
Many of the capabilities mentioned above are in commercial data collection products, specifically PCs with plug-in data acquisition cards. But using these products in an industrial environment presents a number of problems.
First is the difficulty of mounting and protecting commercial components, such as a desktop PC, in an industrial enclosure. Second is the high likelihood of failure after installation due to temperature extremes, shock and vibration, electrical noise, and other conditions common in industrial environments. Third is the lack of certification for use in hazardous locations.
To avoid these and other issues, any EPIC intended for an industrial remote access application should meet minimum requirements, including:
- DIN-rail mounting
- operation from about -20°C to 70°C
- industrial microprocessor
- solid-state drive
- certification for use in hazardous locations
One of the most basic functions for any remote access system is connecting inputs to I/O terminals in an efficient manner.
Control and I/O
Connecting control outputs and inputs should be as simple and foolproof as possible, particularly with the larger point counts to support Industry 4.0 and Industrial Internet of Things. Ideally following industry norms, I/O terminations are made to removable and hot-swappable terminal blocks incorporating a quick connect to the edge controllers that have a captive hold-down (i.e., screw). Terminations made to the block should support up to 14 AWG using accepted industry methods, including spring clamps and screws. Supporting the high point counts for Industry 4.0 and Industrial Internet of Things high-density I/O modules should strongly be considered (i.e., 24 channels per module). Multiple discrete and analog input types and at least 20-bit resolution for analog inputs to support the wide range of control and big data applications should be included. Local LEDs indicating the status of each channel enable local users to verify operation at a glance (figure 3).
In addition, I/O configuration should be simple, with individual I/O modules reporting their identities to the EPIC. Ideally, a local touchscreen will have I/O specifications, wiring diagrams, and channel status to facilitate commissioning and troubleshooting.
Figure 3. I/O modules provide a visual indication of the overall module status, and a touch-sensitive pad activates the display of diagnostic information for each channel on the embedded HMI, simplifying startup, commissioning, and maintenance.
Simplifying edge automation
Remote access used to be a complex undertaking for machine builder and process skid OEMs, with numerous issues related to performance, cybersecurity, and IT details. New automation components and open standards, such as MQTT and Sparkplug, are addressing this issue, making it far easier and less expensive to deploy and support highly secure remote access systems.