By Pepperl+Fuchs |
One piece of wireless technology that’s making a big impact when it comes to industrial communication is WirelessHART, which is the first wireless standard developed strictly for industrial applications.
Let’s take a look at the five most common reasons we have WirelessHART — mobility, flexibility, cable replacement, asset management and retrofit.
Even though moving parts are seldom used in process automation, still, moving parts exist. The most prominent moving parts are rotating or moving tanks and vessels. Rotating parts often are found in wastewater facilities in sedimentation basins. The racks rotate to collect mud and thrash out water. Signals to and from these rotating parts are transmitted via sliding contact. However, the dirty environment and exposure to environmental influences can cause these contacts to degrade over time. Rust, mud, dirt and abrasion of the contacts will cause signals to fail.
Repairing contacts is expensive and would cause a basin shutdown for several days. On the other hand, WirelessHART can easily transfer signals to and from the rotating racks or tanks, and eliminate the need for downtime.
Measurement often is the preferred way to improve processes. However, if a measurement is needed for just a short period of time, wiring isn’t economically feasible, and thus no measurement is made.
A WirelessHART sensor doesn’t need cabling and can be mounted for a short time and then removed. Just put it on and take the measurement. When the measurement is finished, remove the sensor and reuse it at another location. This provides the necessary flexibility to make appropriate measurements when needed to improve product quality or to identify savings potential.
3. Cable Replacement
Plants in process automation usually have a life cycle of 30+ years. In older plants, all signals are wired, and eventually some spare cables are added. But over the years, the need for more information increases because of legal and quality assurance (QA) issues. At some point, the spare cables are used up, and the cable trays are full of additional cables. It would be expensive to add more cables or cable trays.
WirelessHART devices can bridge some distance and ease the need to build new cable trays. Generally, one hop can reach up to 300 m under ideal conditions; with the mesh network, even bigger distances can be covered.
4. Asset Management
Until now, asset management has been thought of as field-device diagnostics. But in reality, all technical equipment in the field is an asset. Every pump, heater, cooler, valve and fan is vital to plant operation. This means it’s important to know the health of those assets to perform preventive maintenance. This saves time and costs and ensures the operation of the plant on a much wider scale than just observing the field devices.
A WirelessHART device can provide feedback about the health of your plant’s assets, which will certainly save money and possibly downtime.
Over time, because of the need for additional information, better asset management, better QA, and legal aspects, old installations are retrofitted to use HART.
Typically, the field devices are wired and have been in operation for many years. Today, manufacturers can choose between wired HART (such as via the distributed control system or via a HART multiplexer) or WirelessHART.
WirelessHART is a secure and reliable solution, simple to implement and certainly worth considering for integration into your process. It also offers other benefits:
- It’s based upon the established HART protocol.
- It uses known tools and procedures for configuration, maintenance and diagnostics.
- It requires minimal training.
- It allows wireless access to existing field devices.
- It can be used worldwide without licensing.