Pepperl+Fuchs has added the ability to connect volt-free contacts to the WILSEN.node wireless sensor node. The WILSEN.node is designed to add Industrial Internet of Things (IIoT) functionality to existing hardware systems, making it a way to retrofit equipment for modern data collection and process control. The newest upgrade to this hardware is the ability to connect isolated, volt-free contacts like switches and relays, which enhances system flexibility, reduces electrical noise, and increases electrical safety.
The WILSEN.node is Pepperl+Fuchs wireless sensor node that utilizes LoRaWAN technology. Image used courtesy of Pepperl+Fuchs
What Is a Volt-Free Contact?
A voltage-free contact (also called a dry or potential-free contact) is used for connecting devices that do not need to be powered but still provide control to a process. In fact, the control mechanism is designed to be isolated electrically from the rest of the control system.
Examples of volt-free contacts are toggle switches and relays. These devices provide process control, but often must be isolated from other control hardware. Each of these devices benefits from being electrically isolated from the rest of the system. For example, the relay could be connected to a pump to control the level of fluid in the system. The pump is now isolated from the rest of the instrumentation system.
The electrical isolation enhances safety, protects hardware, and reduces electromagnetic interference (EMI). For example, switches tend to introduce an impulse signal into the system. That impulse can provide false spikes on sensor signals, flip individual bits in digital signals, and cause other such problems. Startup inrush current on motors can also cause EMI that can bleed into instrumentation signals.
Volt-free contacts, such as relays and toggle switches, can be connected to the WILSEN.node with the use of an adapter cable. Image used courtesy of Pepperl+Fuchs
LoRaWAN WILSEN.node Upgraded
Pepperl+Fuchs’ WILSEN.node LoRaWAN-based wireless sensor node already allows systems engineers to interface inductive and capacitive sensors, such as level sensors, leak detection connections, rotational speed output from motors, flow sensors, and other such devices. Sensors are connected wirelessly via LoRaWAN. By adding volt-free connections, users can save on wiring and headaches for retrofitting machines safely.
Volt-free contacts can be connected to the WILSEN.node via a resistor network and adaptor cable. This allows switches and relays to be up to 10 m away from the WILSEN.node. The cable can also be routed through the housing for a clean, compact installation.
The WILSEN.node utilizes a LoRaWAN network to enable signal transmission over long distances, bringing IoT capabilities to existing systems. Image used courtesy of Pepperl+Fuchs
Retrofitting Control Systems
While many control systems benefit from the additional flexibility provided by volt-free contacts, Pepperl+Fuchs explicitly highlights several industrial examples. The WILSEN.node is already designed for retrofitting applications, and the new connections make it a good fit for machine monitoring, such as for tallying operation hours.
In terms of specific industries, Pepperl+Fuchs envisions this equipment being used extensively in the chemical process industries. They suggest integrating the newest WILSEN.node with pumps, level controllers, and leak detection sensors. It can also monitor HVAC controls, such as moving dampers and shutters, blower motor controls, vent position, and other hardware. Also, dock monitoring and control, like closing and locking bay doors, detecting trucks, and other such tasks, can be integrated with the updated WILSEN.node.
