• By Bill Dehner
  • March 31, 2020
  • Operations & Management
Maintenance technicians can respond faster, and even prevent problems, therefore saving money

By Bill Dehner

The classic tool kit for an industrial automation maintenance technician typically included assorted hand tools and a multimeter. And for many years now, the tool kit has likely included a laptop computer for the technician to interface with programmable logic controllers (PLCs), human-machine interfaces (HMIs), and other intelligent industrial devices and instruments. Another key element is likely a phone or radio, so operations personnel can contact the technician if trouble is observed. The discovery and notification of trouble is where remote monitoring can be used to improve upon existing practices, and why it should be an integral part of every technician’s tool kit.

An early step for any maintenance activity is detecting the need. Some maintenance is performed on a calendar-based schedule, but many activities are only initiated when something breaks. A range of remote monitoring technologies are helping technicians respond more quickly to failures, and to troubleshoot some problems from afar, or if this does not suffice, to arrive at the site with the right parts and tools. Remote monitoring can also guide more efficient proactive maintenance programs to address small issues before they escalate into major problems. These aspects take on even greater importance when maintenance staff must support many geographically remote sites (figure 1).

New equipment, systems, and entire manufacturing sites can be designed with built-in remote monitoring capabilities. However, there are also many options to add remote monitoring to existing operations populated with older and often standalone equipment. Making industrial systems smarter and available over the Internet in this way is often termed as an Industrial Internet of Things (IIoT) initiative, or digitalization.

This article looks at some technologies for helping end users add modern IIoT and remote monitoring options incrementally to any type of existing system. By adding a mobile device, such as a smartphone or tablet into their maintenance tool kit, technicians can provide faster and better service while cutting costs (figure 2).

But before we get into the use of modern technologies, let’s look at the evolution of remote monitoring.

Connectivity over the years

Industrial automation digital technologies have certainly evolved through the decades, although to many observers the progress has often appeared to be plodding along, well behind the footprints left by consumer electronics. Reasons for this lag include the need for industrial products to provide extreme operating reliability, be maintainable for years, and be robust enough to survive harsh environments.

Basic operational dependability was the foremost concern, followed somewhat by ease of configuration, and even more distantly by remote connectivity. In fact, eventually remote connectivity became a point of concern from a security standpoint, but these concerns were outweighed by its usefulness during initial installation and over the life of the automation system.

Here are some milestones of industrial digital connectivity, in roughly the order they became available:

  • Originally, core PLC and HMI devices required direct local connection and specific software.
  • Plant networks improved upon this situation by letting users connect from anywhere on a site.
  • The first remote monitoring setups involved phone modems, direct to a target device and eventually to the plant network.
  • Wi-Fi networks advanced to let users connect wirelessly.
  • Internet connectivity made it possible to view HMIs and some PLCs from anywhere via web browsers.
  • Now many devices have Internet/cloud connectivity, so users can use mobile devices with device-specific apps for easier access.
  • IIoT-type devices can add remote monitoring without affecting existing automation systems.

Perhaps counterintuitively, the technical difficulty of remote connectivity has become generally easier as the available options improved. Early efforts required special cables, vendor-specific protocols and software, and dealing with slow and intermittent connections. As networking became a common infrastructure-like utility, and standards have streamlined the protocol options, the situation has improved greatly.

The result is that instead of remote connectivity being an esoteric option reserved for designers and engineers at the beginning of a project, it has been democratized through ease of use, so operations and maintenance personnel can take advantage of it throughout the life cycle of an automation system.


Figure 1. Remote monitoring is a key technology for helping maintenance personnel support multiple remote sites with many types of equipment.


Figure 2. Maintenance personnel today are likely to include a laptop computer and smartphone as part of their toolkit.


Keeping an eye on the HMI

For many troubleshooting issues, it is eventually necessary for maintenance personnel to dive into the PLC code to see what it is or is not doing. Fortunately, at many sites, the first line of defense in these situations is supported by an HMI, which can provide helpful information. Local operators can view equipment status and alarms to identify what may be causing a problem.

At the first sign of trouble, operations personnel typically contact the maintenance department. Time is saved when maintenance personnel have their own HMI station, or the ability to remotely connect to the operator’s HMI, in either case so they can use the HMI’s visualization to guide their maintenance efforts. Many HMIs support browser-based remote connectivity, making it possible to remotely view displays on any network-connected computer or mobile device (figure 3).

With the foreknowledge that maintenance personnel will be taking an active role in monitoring equipment and systems via HMIs, it becomes more important than ever to develop detailed diagnostic PLC code and HMI graphics for use by maintenance personnel.

Beyond troubleshooting, the integration of run-time hour timers and equipment cycle timers are the first steps toward preventative and predictive maintenance. Just like a modern car alerts the owner to an upcoming necessary oil change, based on mileage and driving conditions, any contemporary automated system or machine can and should track similar indicators. Remote connectivity makes this information readily available to the maintenance personnel who need it.

The inverse of availability in this case is security. Even within the local area network (LAN) at an operations site, it is important to allow only authorized personnel to access HMIs and PLCs. When industrial automation systems are connected through a corporate wide area network (WAN) and to the Internet, security becomes even more of a concern.

This awareness about security has led to the incorporation of IT-type technologies, such as virtual private networks (VPNs), for industrial automation networking. Users can connect with LANs/WANs from anywhere securely over VPNs, but the downside is that VPNs can be difficult to administer.

For this reason, some industrial automation suppliers have developed mission-specific VPN implementations to help end users easily benefit from VPN connectivity while requiring minimal configuration effort and no IT involvement. This type of innovation provides a best-of-both-worlds solution for operational technology (OT) end users, who can best benefit from remote connectivity but may not be staffed to implement it.

The cloud changes connectivity

Before browser-based and Internet/cloud methods, remote connectivity required the design and support of specific hardware, software, and configurations. Remote connectivity innovation was not destined to end with the ubiquitous web browser, however. Interacting with web-type HMI displays over a VPN connection is workable, but sometimes can be a little inelegant. Fortunately, the rise of consumer-based smartphones and associated apps provided a new option.

The latest remote connectivity options use cloud capabilities and apps to homogenize and simplify access, so users can focus their efforts on the real issues at hand: identifying problems, often proactively, and fixing them.

Automation vendors now offer cloud services that simplify access by establishing secure VPN connectivity to any number of remote sites and systems, and serving up HMI displays and PLC data on end user computers and mobile devices (figure 4).

For a nominal monthly charge, users can deploy this functionality companywide. The capability is scalable, so end users can grow it at their own pace. This lets them start small with a few machines as a trial, and then deploy the service to a fleet of equipment.

Mobile apps are created to be aware of the particular needs of HMI and PLC users. Therefore, these apps streamline the visualization process, and offer specific features for maintenance users, such as the ability to monitor tags directly within a PLC.

Beyond connectivity and visualization, these industrial cloud services have other advanced functions like data logging and alarm/event notification. These features are common to large supervisory control and data acquisition (SCADA) implementations. However, many end users operate dozens of standalone or lightly integrated equipment and do not have an overall SCADA system. Cloud services and remote connectivity make it easy for end users to take advantage of such functions without having to create extensive systems.

Remote connectivity is not an all-or-nothing proposition. For new projects, users can certainly select HMI and PLC platforms with these features. More likely, many users have lots of operating equipment and systems already installed, and it does not make sense to completely retrofit each with new automation. Instead, they can gain remote connectivity benefits by adding a modern PLC or HMI to existing systems, and then using these components to concentrate important information and make it available via the cloud. It this way, maintenance personnel can add the IIoT features they need to help them perform their work proactively without disrupting existing operations.

IIoT as a parallel path

As noted previously, the earliest remote monitoring systems usually required a heavy emphasis on adjusting the underlying PLC and HMI systems to provide the necessary data. Newer cloud solutions have more alternatives for improving automation systems by adding IIoT capabilities.

However, many users are reluctant to meddle with existing automation systems that are working just fine. Or, they may want to monitor equipment that has hardwired controls or other limitations. For these cases, a new class of lightweight, cloud-ready devices let users overlay remote monitoring functionality without disrupting existing systems (figure 5).

For applications only needing to monitor or perhaps remotely command a few discrete points, a wireless portal is an inexpensive and easy-to-install option. These portals may also support Modbus RTU communications, which is a classic but still viable industrial communications protocol supported by many types of equipment. Users can easily install one or dozens of these gateways at local equipment, and they use Wi-Fi networks that are existing or can be added quickly and inexpensively.

These portals have free cloud subscriptions with options for higher-data plans. Typical cloud features include:

  • user-configurable real-time dashboards (similar to HMI displays)
  • cloud storage for data logging
  • ability to download data as a CSV file
  • email and/or push notifications on alarms
  • scheduled remote access
  • mobile device monitoring

Other edge devices like MQTT gateways can integrate with typical Modbus field devices and report information up to a cloud-based broker using the MQTT protocol. This approach involves a little more user configuration than a dedicated cloud-based portal system, but it has even more flexibility for users to deploy IIoT capabilities to existing equipment.

When a maintenance group knows certain automation data could provide proactive notifications, installing a parallel system of cloud-connected edge devices can be a cost-effective way to add these IIoT features without interfering with existing functionality.

Reactive and proactive results

Maintenance operations want to use remote connectivity and monitoring to respond to problems faster, or avoid them before they happen, and therefore save money. Downtime can be costly to any manufacturer, but when dealing with a high-dollar product, like oil production, the costs of a shutdown can be astronomical. Some offshore wells can produce upwards of 34,000 barrels of oil a day, and with oil prices around $50 a barrel, just one hour of a shutdown can cost more than $70,000 in lost production.


Figure 3. Industrial HMIs, like this AutomationDirect C-more, have native remote monitoring capability, for maintenance access via a laptop or mobile device.


Figure 4. Cloud-based services, apps, and hardware (such as AutomationDirect StrideLinx) help users establish secure VPN connections and enable mobile app monitoring of their automation systems.


The oil and gas industry is well aware of the costs a malfunction can have and has taken many steps to prevent these occurrences. Remotely monitoring critical assets is an important part of that prevention. Communication to these offshore platforms is well established, and many companies continuously monitor oil production components remotely.

For example, to avoid any unexpected valve failures, whenever a command to close or open is given, the automation system records the time it takes for the valve to complete its action. This information may be determined in the controller, but if it is not communicated to a higher level then it is impossible for action to be taken proactively.

By implementing remote connectivity and monitoring for crucial activities, it becomes possible to compile this data and analyze it to determine which valves are sticking or are on the way to failure. This data gives operators and technicians, both on site and off, a heads-up and allows a quick and proper response to correct the condition with scheduled maintenance.

Maintenance teams should start by addressing the most troublesome or expensive problems. As their comfort level with remote monitoring improves, it is easy to expand the types of monitoring to encompass other parts of operations.

Expand the tool kit

Today’s maintenance technicians are ready to expand their tool kits by adding a mobile device for remotely monitoring equipment and systems. Remote monitoring gives these personnel the ability to respond to problems faster, and even proactively prevent them.

For users with existing systems and standalone equipment, there has not always been an easy answer for improving remote connectivity. It has been especially daunting to plan an overall platform able to connect to many different remote systems consistently. The latest cloud-based options make building-in or adding-on remote connectivity a straightforward activity, helping maintenance personnel focus their efforts on keeping their manufacturing and production plants running.



Figure 5. To add IIoT capabilities without interfering with existing operations, users can install AutomationDirect Pocket Portals and access the information through an associated cloud service.

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About The Authors

Bill Dehner, has spent most of his 11-year engineering career designing and installing industrial control systems for the oil and gas, power, and package-handling industries. He holds a bachelor’s degree in electrical engineering with an associate’s in avionics from the U.S. Air Force. He is currently a technical marketing engineer at AutomationDirect.