The world is changing, but more specifically, it is evolving. In all industries today, the buzz is around wireless monitoring via the “IIoT” or the Industrial Internet of Things. This technology focuses on cutting edge devices that enhance or improve data collection, decision making, interconnectivity, and communication between the prime movers and the internet. This can range from the heat pump in your home to the large pumps at a water treatment facility. Connecting these pieces of equipment to the internet allows for quick, concise assessment of the equipment’s health. In addition, it allows for timely diagnosis and repair before the equipment has a catastrophic failure.
This all stems from attempting to improve the mindset of the facility, moving from a reactive maintenance program to a proactive program. Reactive maintenance is waiting for a problem to develop. This is often due to a lack of information or resources before allocating the time and labor to repair it. Reactive maintenance can be risky and expensive. Unfortunately, with increasing workloads, smaller staffs, and tightening budgets, preventative maintenance is no longer the best, most efficient strategy. Vibration routes on a periodic monitoring basis have been relatively successful in the past. But again, the workplace environment is changing, and tough decisions have to be made on which equipment to monitor and which to deem as “run to failure.”
Enter the Internet of Things. Over the past decade, more and more products are entering the marketplace to either replace or enhance the standard route-based data collection. These new products offer more sophisticated analyzers, wireless sensors, and an integrated network of data acquisition. These devices can have a vast array of functions. Many come with all assortments of necessary infrastructures. Evaluating and selecting equipment like this requires a deep understanding of the customer’s situation. Furthermore, it requested data to make informed, intelligent maintenance decisions. Every situation is unique and requires meticulous planning to be effective.
The demand for reliable, accurate data is essential to achieve the step-change for improving a preventive maintenance program approach. While technology can offer advantages, it is important for the solution to not be more costly than the alternative. When considering technology, it comes down to the cost of the product, infrastructure, and integration costs. In addition, operators need a full range of solutions that provide maximum flexibility. These solutions span from vibration accelerometers, temperature probes, pressure transducers, flow meters, data transfer devices (4-20mA, digitals), and more. However, one must also consider the performance limitations of the system, such as transmission range, along with flexibility in communications.
IIoT displays overwhelming success and receives a great deal of attention. It improves the efficiency of routine route data collection. In turn, it’s not just a standard time-based task, but becomes an intelligent gathering of critical information. This allows operators to focus on assets that require attention rather than spending man hours evaluating perfectly healthy equipment. To take advantage of the opportunity that IIoT can provide, it’s important to understand the tradeoff in technology. Furthermore, operators must consider a service that maximizes the return on investment.
Operating equipment is broken down into two fundamental categories:
The Balance of Plant assets represent the largest population of equipment at any site. Typically, most equipment is not particularly critical and may not directly impact process control, safe plant operation, or auxiliary systems. This term derives from the power industry. It associates the delivery of power rather than the actual generation of it. However, the idea can extrapolate to any other industry. These assets are suitable for entry-level, battery powered devices, but may benefit or require AC/DC powered devices as well.
1. Battery powered devices offer performance data such as overall vibration levels (Velocity RMS/acceleration/peak frequency), pressures, flows and temperatures. This data transmits in an ideal interval for obtaining the necessary information while preserving battery life.
2. In remote, non-accessible areas, such as cooling towers, a power (AC/DC) transmitter may be a better solution. This can eliminate battery maintenance and provide more frequent transmission without a concern to battery life. It’s something that operators should evaluate when considering IIOT equipment.
Key Processes may benefit from AC/DC solutions, which guarantee that transmitter battery issues do not halt or lose critical data for collection. Furthermore, this ensures that near real-time, reliable, and accurate data is available at operators’ fingertips, 24-hours per day.
Wireless Transmission can refer to any number of transmission protocols; for example, Wi-Fi, Bluetooth, ISA 100, Wireless-HART. These protocols either operate in the 2.4GHz range, or in low frequency bands such as LoRaWAN / 900MHz. Advancements in technology make these protocols reliable and secure – to varying degrees.
Although many industries rely on 2.4GHz transmission protocol for business networks, it has some limitations. For example, there is a limit to transmission range of these protocols. First, they are typically line of sight, meaning that the transmitter and receiver require a clear path between the two. Use of 900MHz protocols offer the same, if not greater, data security. Furthermore, it’s often omnidirectional and utilizes spread spectrum, frequency hopping transmission. Frequency hopping can ensure reliable data transfer over much greater distances. Once a gateway receives data, integration into the business network or cloud-based platform is equally simple across the board.
As technologies continue to mature, it’s worth mentioning that LoRaWAN (bi-directional) networks utilize 900/868 MHz spread spectrum technology. They rely on an unmodulated carrier in FM chirp, which spreads energy across a wider band. This bi-directional technology is evolving. It shows tremendous success in urban environments with ranges from 1.2-4.3 miles (2-7 km), depending on the environment. This technology is in use in several sub-metering markets. Furthermore, integration of asset performance data is easily achievable. This is especially true for remote stations such as lift stations and pump houses.
Initially, wireless telemetry experienced a great deal of “data collision.” This is due to a high number of transmissions over a narrow band of frequencies. To avoid this problem, technologies now rely on wireless data that can transmit over numerous bands. The term “frequency hopping” refers to this strategy.
Spread spectrum provides secure and noise‐free radio transmission and ideally suits data communications. It operates by spreading the signal over a wide range of frequencies instead of concentrating it around a center frequency. Spread spectrum is a modulation technique, along with other similar types such as amplitude modulation (AM) and frequency modulation (FM).
There are currently three predominant spread spectrum bandwidths of wireless monitoring: 868 to 902-928 MHz, 2,400 to 2,483.5 MHz and 5,725 to 5850 MHz. The major advantage of spread spectrum technology is the ability to spread the signal over a wide band at very low power. Consequently, the signal has a low probability of interference or interception.
Interference during radio transmission happens when signals take multiple paths or outside forces affect them such as weather, magnetic fields, electrical fields, etc. Spread spectrum technologies provide redundancy of signals, which greatly reduces the risk of losing a signal to interference or interruption of a signal. It also minimizes the effects of walls, structures, and terrain on the signal. This technology allows data or information encryption on both the sending and receiving ends of the process.
Before the development of this technology, transmitting signals would require line of site. But this was not conducive to plant environments as many data points are buried within a facility. With “omni-directional” transmissions, the signal broadcasts over a 360‐degree spherical profile in a range of approximately 3/4 mile (1.2 km). In many instances, signal deflection by structures such as process vessels, pipe racks, or other metallic objects will enhance the signal’s ability to transmit back to the receiver.
The new generation of telemetry relies on such technologies as Spread Spectrum (frequency hopping), Omni-directional Transmission (360-degree transmissions), and Data Packaging (bundling multiple of the same data bits for transmission). All have their own unique characteristics that enhance the transmission of any radio signal. But by combining them, they offer a powerful “data highway” that is reliable, cost effective, and with an ROI that far outweighs that of hard wire and conduit in most instances.
Inherent to the adaptability of these technologies is the way the signal is conditioned (or readied) for transmission. Such conditioning would include data packaging, signal encryption, unique IDs, etc. When all these technologies work in concert, they afford the end user the ability to transmit data in a reliable and uniform manner. Then, and only then, can operators reliably address the issue of data acquisition and control.
The system architecture, in terms of defining the initial footprint of the wireless monitoring system’s integration, is dependent on the end users’ needs – now and in the future. Critical components for the backbone of any wireless communication system include the:
When considering multiple points within the facility that closely bundle, there are available wireless units that have the capability to collect several data points or discretes via either a Modbus or analog / digital interface and transmit all the data back to the supervisory control systems through a wireless communication link. It’s important to note that each addressable data point does not have to be stationary. In many instances, such points as temperature may be mobile points that still track wirelessly since the architecture of the wireless system features a footprint for that specific facility.
Collection of performance data points such as vibration, temperature, 4-20mA signals, flows, pressures, and more provides an in depth look at the health of a piece of equipment at a given time. Relaying this information into a data collection suite with built-in historian allows for the data to be saved and trended over time. This provides the analyzers to see how performance changes over time either due to degradation or system process changes.
As an example, a 60 year old cooling water pump was running in an industrial plant. These pumps require a dedicated team of 3 technicians based at the pump house to immediately address issues that may arise during operation. Typically, vibration routes were only taken once per quarter to provide a snapshot of the pump health. But after a wireless system installed on the pump, it detected early signs of cavitation. The pump was proactively shut down, inspected, and confirmation of cavitation on the impeller was found, all thanks for wireless monitoring.
Further analysis revealed that the system was operating improperly and starving the pump of the required suction pressure. The issue was corrected, and the pump returned to service. A failure of the impeller would have resulted in a cost of $65,000 in hardware, multiple days of labor costs, and a loss of $1.6M in revenue every 15 minutes due to lost production. The wireless monitoring system saved the pump and kept the plant operating. Currently, the station no longer houses technicians at the pump house as the wireless system monitors the pump health constantly, allowing those technicians to be used more effectively in other areas of the plant.
Now that the overwhelming benefits of wireless monitoring are explained, the sensible follow-up is: “how do I incorporate this into my existing facilities SCADA or plant control architecture?”
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