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The evolution of 4G technology has led to many changes in remote device monitoring in recent years. By using cellular networks and stand-alone remote devices such as data loggers, PLC’s and embedded PC’s, people are finding it easier than ever to manage assets on remote sites.

Remote Access diagram
Data loggers record important data over time via sensors or external instruments. 

PLC’s are used to control processes or machinery, such as switching on motors or heaters in response to measured signals. 

Embedded PC’s are computers (often running a variant of Windows) set up to perform a single task in a mission critical scenario. 

It is now easier than ever to provide remote access to such a data logger, PLC or embedded PC, and other similar equipment, via a smart cellular 4G router which is installed on site.

The need by companies to manage their remote assets in the most efficient way has also been recognized by both wireless carriers and router manufacturers. Industrial cellular routers are designed with features specifically needed for monitoring equipment in unmanned locations. In addition, telco’s have added the required settings to their networks to make remote access possible. Finally, while bandwidth and cost limitations have in the past made it hard to achieve the true potential of wireless connectivity, today the relatively low cost and high bandwidth available on cellular networks makes remote access a cost effective option for many industries.

The future of remotely administering devices is here

The paradigm of remote device management is now changing courtesy of recent advancements in several key areas. Firstly, most cellular network providers have released faster wireless technologies such as 4G/LTE, with an unprecedented coverage across Australia. Companies such as Telstra are offering speeds in the megabits per second range, and coverage to over 99% of Australia’s population. Secondly, to gain remote access to an unattended site, most regular mobile broadband connections are inadequate, because they utilise private IP addresses that cannot be found on the public internet. However carriers are now able to offer public IP addresses on their cellular connections, by special request, and dedicated M2M SIM cards provide even more advanced features such as virtual private IP networks. This means that remote devices can now be “seen” on the cellular network and accessed from anywhere.

The challenge of the IP address

Netcomm NTC-220 Industrial 4G Router

Photo courtesy of Netcomm Wireless

Despite the availability of public IP addresses from some carriers, another challenge remains: the IP addresses provided by the cellular network are not static, and are likely to change from time to time. How, then do we know what IP address to target when attempting to access a remote device? The simplest solution to this problem is to use a dynamic DNS service.

Regular DNS services are everywhere on the internet: the DNS provides the mechanism to map a user-friendly internet address (URL) such as www.esis.com.au to the IP address of the server where that resource resides (such as 182.160.156.110).

Dynamic DNS services do the same thing, but with 2 key differences: firstly they allow the IP address to be dynamically updated by the remote device as and when it changes; and secondly they set up the DNS service with a very short expiry time, thus forcing users’ computers to always check back with the DNS service for the latest IP address.

This means that where a remote device is accessible via a cellular 4G router, the device can always be accessed by using a pre-configured internet address (URL) associated with the Dynamic DNS service, no matter how often the router’s IP address gets changed by the cellular network.

The dawn of dedicated M2M cellular services

In the last few years a new breed of cellular service has appeared on the market: the M2M cellular service. This is a service that uses the same cellular backbone as traditional mobile broadband, but the SIM cards are specially provisioned with features needed by remote unattended equipment. 

Significantly these SIM cards can be set up to form a “virtual private network” between devices in a group. In this kind of configuration, the cellular network allocates private, static IP addresses to all the devices in the group, and each device is able to “see” all the other devices in the group directly. The devices may or may not also have access to the wider internet. Hence it becomes very simple to configure a reliable network of remote devices, without the worry of losing configurations or the devices being compromised by hackers on the internet.

The Issue of Reliability

Where remote devices are on an unmanned site, or the site personnel are not qualified to maintain the equipment, reliability becomes a key factor in the remote access system. Regular cellular modems (USB “dongles” or domestic wifi cellular routers) are not designed with remote unattended usage in mind. Typically these devices are prone to crashing, and dropping the cellular network and not being able to re-establish connection automatically. For personal usage this is not a major problem as the device can be reset or unplugged/re-plugged by the user. However in a remote access scenario this is such a problem that it can negate the benefits of the remote access system – most companies would not want to have to send a person to each remote site every time the router crashes.

The solution to this issue is the industrial grade wireless 4G router. These devices are specifically designed for providing remote access to devices and systems via cellular networks. They typically have the following extra features:

  • Physically rugged design for extra reliability in high temperatures or high vibration environments
  • Internal watchdog timers to automatically reset the router if a crash occurs
  • Carefully designed firmware to ensure that network connectivity is always restored after any interruption
  • Locking connectors to avoid plugs shaking loose
  • Remote access feature support including dynamic DNS, port forwarding, remote configuration, strong firewalls, etc.

Expert guidance is recommended

Aside from the issues of IP addresses and reliability, there are several other possible pitfalls that appear when one tries to implement a remote access system. For example if you’re using a 4G router, you’ll also need to configure port forwarding, and make sure the IP networking is configured correctly in all the devices involved.

Other common pitfalls revolve around the specifics of the equipment one is trying to gain access to remotely. Equipment manufacturers often make assumptions that their Ethernet-based (or serial-based) equipment will only be accessed on a local, wired connection. Cellular remote access can be different in that it introduces extra time delays and the possibility of dropped data packets or a dropped connection, as well as the presence of one or more routers in the network.

To overcome this kind of issue, it is useful to have detailed knowledge of the specific equipment being used and the possible ways the settings can be adjusted to cope. In some cases it may even require a change of approach or the use of different equipment in order to facilitate remote access.

Hence when you want to set up a remotely accessible system, it is always advisable to speak with an expert who not only understands the equipment but also understands the challenges of remote access. At Esis we pride ourselves on our in-depth knowledge of a wide variety of equipment and our extensive systems engineering background, along with experience setting up remote access via 3G and 4G routers.

The future is bright

If all these factors are addressed, large and small enterprises can effectively manage their assets that are located in multiple locations whilst achieving significant cost savings. They can get the data they need anytime they want, in a reliable manner. With the developments that have taken place in recent times, cellular networks and industrial electronics can be used to achieve so much more than ever before.

For expert guidance on your next remote access project, please contact Esis – our team will be more than happy to help.

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