The road to Wireless – which wireless standard suits you best?

WiFi, Bluetooth or Zigbee? Tom McKinney of HMS Industrial Networks offers a review of the available short range wireless standards for industrial applications.

Tom McKinney, Business Development Manager at HMS Industrial Networks

Recently the buzz around Industrial IoT has grown to a deafening roar. The market for IIoT devices is projected to grow exponentially over the next several years as businesses start to capture more data regarding their operations. That data will be used to monitor and optimize processes, and as companies learn to use the data they capture to improve processes, the result will be increased productivity. Beyond internal productivity, this data may lead to improved company-to-company operations benefiting both the producer and the customer.

Multiple technology advancements have converged to make large-scale Industrial IIoT deployments possible. These advancements include reduced cost of data storage, lower power RF solutions and higher levels of network accessibility. Another important enabler for Industrial IoT is wireless standardization.

Wireless is nothing new
Wireless networks have been used for over 30 years in the industrial market. In the past, these networks were typically sub 1GHz proprietary systems. The solutions used simple modulation techniques like amplitude-shift keying (ASK) or frequency-shift keying (FSK). Radios that supported these types of modulation could be created easily with a handful of discrete parts. The drawback of these solutions were a complete lack of security and limited bandwidth.

Over the last twenty years, several standards have been developed to define robust radio solutions. The most recent standards are secure enough for broad deployment. In addition, several new free-to-use frequency bands where introduced in the 80s including the 2.4GHz and 5GHz bands. Deploying a standardized radio solution today is a cost-effective secure way to both monitor and control devices in the field or factory. Given the number of wireless standards to choose from, the question becomes which standard is the right standard to deploy.

Summary
1) WiFi
a. Pros
i. Highest Bandwidth up to 600Mbits/s with 802.11n
ii. Fixed 25 MHz or larger Channels
iii. Support for 2.4 and 5GHz channels
iv. Extensive security features
b. Cons
i. Range is lower with higher data rates and 5GHz
ii. Not a good match for battery powered sensors
2) Bluetooth/BLE
a. Pros
i. Very low power
ii. Massive deployed
iii. Very good performance in congested or noisy wireless environments
iv. Ease of use, no frequency planning or site map requirements
b. Cons
i. Max data rate of 2Mbits/s
ii. No automated roaming standard
3) Zigbee
a. Pros
i. Very low power
ii. Fixed channels between WiFi channels in 2.4 GHz band
iii. Support for sub 1GHz bands
b. Cons
i. Complicated mesh network
ii. Max bandwidth of 250Kbits/s

So let´s take a look at the three most common wireless standards deployed in the 2.4GHz band: Bluetooth, WiFi and Zigbee.

WiFi
WiFi or IEEE 802.11a/b/g/n is the widest deployed consumer and enterprise wireless TCP/IP network solution. WiFi is short for Wireless Fidelity and is a standard used to identify Wireless Local Area Network (WLAN) devices. The committee managing this standard is aims to create the best possible wired TCP/IP network replacement. The committee prioritizes security and speed over all other tradeoffs. As a result, 802.11n has the highest bandwidth of any short range wireless standard. The drawback is power consumption and processing power required to effectively manage the 802.11 stack. These drawbacks created a gap in the market and several standards have emerged to address the very low power wireless market.

Bluetooth
Bluetooth and Zigbee were both introduced to address markets not serviced well by WiFi. The Bluetooth standard addressed the needs for a low power Personal Area Network (PAN). A PAN is defined as the network that surrounds a person or a smart device. The requirements include fast association, simple human-to-machine interfaces and low power. In a PAN, multiple transmitters can be placed very close together – Bluetooth includes timing to ensure device transmitters don´t overlap. Bluetooth was also designed under the assumption it would have to co-exist with WiFi and includes a frequency hopping algorithm to ensure Bluetooth messages can get through even when multiple WiFi channels are active. Finally, because Bluetooth uses a very low power transmitter, it is less sensitive to multi-path compared to WiFi. As a result, Bluetooth can be deployed successfully without extensive RF site reviews and planning. The system is very resistant to noise and interference.

Zigbee
Zigbee is based on IEEE 802.15.4 which is a general-purpose, low-power wireless radio standard that allows different protocols to be built on top of the standard radio. Zigbee set out to support low power sensor networks capable of covering a large area. Zigbee uses meshing networking and a very aggressive power profile to meet the needs of this niche market. Zigbee´s protocol is designed for quick turn-on and turn-off, thereby saving power. Several other protocols have been built on top of 802.15.4 including ISA100, WirelessHART and 6LoWPAN.

Bluetooth Low Energy
Bluetooth Low Energy (BLE) was introduced as an update to the Bluetooth standard. Leveraging some of the techniques used in 802.15.4, BLE was able to achieve even lower power points when compared to Zigbee and support many of the features originally created by the Zigbee standards effort.

Selecting the standard for you
So which standard is the right standard to deploy? That depends on the system requirements. In summary, WiFi has the highest bandwidth and most comprehensive stack but Bluetooth, BLE and Zigbee offer features ideal for particular applications. For example, if monitoring battery-powered sensors over a very large area, Zigbee would be the ideal standard. Bluetooth/BLE works well as a cable replacement point-to-point technology or for monitoring sensors over a smaller area. BLE has a huge installed base of tablets and phones making it an excellent choice for human-to-machine interfaces.

Although technology standards may vary, there is no doubt that more and more applications will be wirelessly connected in the near future. With the advent of Industrial IoT, billions of devices will need to hook up to the Internet, and many of these connections will undoubtedly be wireless.

Get your head out of the clouds! – 3 ways to reduce maintenance costs of power generators

Henrik Arleving, Product Line Manager, HMS Industrial Networks presents three ways to reduce maintenance costs of power generators.

Henrik Arleving

Keeping track of a fleet of power generators can sometimes be a head-in-the-clouds-experience. It can be hard to focus on the right actions simply because there is not enough information on fuel levels, oil pressure or battery status for each genset. With a cloud-based remote management solution you can have immediate online access to generator parameters via a regular web browser. Below we propose three ways in which remote management can be used to reduce operating costs and improve control.

1) Perform service only when needed
Power generators are often serviced according to a pre-determined service schedule. By understanding how the generator has been operated, it is possible to plan service more dynamically. As site visits are costly, you are able to optimize the service costs by only sending service teams to generators that actually need service.

The challenge is to know when service is needed at each individual site. With a remote management solution, you can check operating hours, oil pressure, battery status, coolant temperatures, generated power output, fuel level, GPS position etc. A notification may also be generated whenever a critical level has been reached, for example if the generator has been running more than expected. We may then send a notification when the running hours exceed the service interval.

By being able to analyze the operation of each generator remotely, you will be able to understand their health and more efficiently schedule service visits in the field.

2) Test start generators remotely to reduce start-up problems
Just like a car that has been parked for an extended period, a generator engine that has not run in a long time is likely to have start-up problems. For back-up power generators that are not operated very often, it is important to regularly perform operational tests. Remote test starts can be made with a remote management solution that has control capabilities and is connected to the generator controller. With a simple action such as a remote operational test, you may increase the likelihood of the generator working the day there is a power outage and the generator needs to perform.

Typical web dashboard from which a power generator can be monitored and even started or stopped remotely.

A well-maintained generator operates better and has lower operating costs since unplanned service visits often mean substantial expenses.

3) Minimize and reduce the effects of fuel theft
Fuel theft can be a significant problem. In certain regions, as much as 40% of genset fuel is reported to be stolen.

Avoiding fuel theft completely might be difficult since it is often stolen a bit at a time; during transportation, at fill-up, or at the power generator in the field. However, a remote monitoring system that connects to a fuel sensor can be used to ensure that the right amount of fuel is delivered at a refill. By using an intelligent level sensor, it is possible to track the fuel level of the tank. The fuel sensor can be calibrated to sense a full tank and by knowing this we can verify that the tank is properly refilled. A good fuel level sensor is able to detect variations down to 3-5 liters.

An abnormal decrease in content may be detected and indicate that the fuel is being stolen. With a remote monitoring system that supports alarms, a notification is sent immediately when the theft occurs. Even if it might be hard to catch the thieves, we are at least aware that the fuel has been stolen and we can schedule a refill to ensure the generators have the fuel needed to operate.

Tracking the level of fuel in a tank increases the awareness of what happens to the fuel on site and helps users understand when theft occurs. In some cases, where organized theft is common, this may help detect patterns and take action.

Remote monitoring puts you ahead of the game
Modern remote monitoring technology enables instant access to data from equipment in the field. While we are able to use this technology to reduce operating expenses as described above, it also brings us other benefits. By being able to have full control 24/7 and be instantly notified of any operational issues, the end-user also receives improved service quality.

How cloud-based remote management works
A communication gateway connects to the genset control panel, usually via serial communications or by using a popular open protocol such as Modbus RTU. The gateway sends data via the Internet or the mobile network (3G/GSM/GPRS) to an online data center in the cloud. Service engineers can access the data center through a regular web browser or smartphone and see live data from the power generators. This means that no IT expertise or programming is necessary. Alarms and notifications are sent whenever certain thresholds are reached.

So which solution should I choose?
There are a couple of different solutions for remote management of power generators available on the market. A few things to consider are that the solution should be able to send information via the mobile phone network since many power generators are placed in remote locations. It is important that the solution is “firewall friendly” so you don’t have to spend time on security issues and access rights.
Some remote management solutions, like the Netbiter remote management solution from HMS, have specialized solutions for power generators including pre-defined configurations for a range of for control panels from different manufacturers as well as built in features for fuel level management etc.

What are the costs involved?
You pay for the communication gateway which connects to the power generator. Most modern remote management solutions offer different service levels for cloud access. Free versions with basic functionality are often available offering a very quick return-on-investment.

No matter which solution you choose, the ROI will most likely be quick. A service visit is usually the same cost as a single remote management gateway meaning that you may have a payback time of only a few