Wired remote sensing systems are the norm, especially in the oil and gas industry. In these configurations, sensors monitoring various assets are equipped with outputs that require hundreds of feet of wire to connect to a PLC. Analog 4-20mA current loop and Modbus interfaces are examples of communication protocols that can cope with long cable runs.
However, while offering advantages over taking manual readings from sensors or gauges, wired systems can pose limitations depending on the application regarding installation costs, sensor flexibility, and environmental influences. For example, if a remote monitoring application requires multiple sensors to monitor various parameters, a wired system requires each sensor be wired back to the controller using an interface port. For large systems, a wired system requires a large interface panel with many different interfaces.
A wireless system, on the other hand, will often have a digital communications interface (Modbus RS485), allowing for many sensors to be wirelessly “connected” to the controller through a single port. While beneficial when configuring a new controller, changing from a wired interface (with lots of individual input ports) to a gateway-based wireless system with a digital interface requires pre-planning.
Here are some factors to consider when evaluating a move to a wireless remote monitoring and control system instead of upgrading an existing wired system.
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When moving from a wired solution to a wireless one, consider all the aspects of the job. Is there a problem with what you have now? If so, are you willing to change the interface at the controller understanding that this change will allow you to take in much more data and diagnostic information than you had before? Is it more cost effective when considering the absence of cable, trenching and interface requirements? Deciding when to “pull the trigger” is the hardest part. SignalFire has found its customers benefit in the long term with a wireless system.
Find out why a chemical plant chose a wireless remote monitoring system over a wired system when adding level and temperature parameters to its tank level monitoring application by downloading the application note.
Scott Keller is the CEO and CTO at SignalFire Wireless Telemetry.