Weidmüller offers solutions for the signal connections between measurement devices or actuators and the control unit – even for hazardous area applications. This includes signal converters (isolators or barriers), surge protection components for instrumentation and control, as well as marshalling and distribution terminals with integrated shield/PE connection.
All three signal circuits are protected by VARITECTOR against lightning and surge voltages. For intrinsically safe signal circuits the blue VSPC-EX version (left) is used. Certified at SIL 2 or SIL 3, VSPC can be used in safety critical signal circuits in accordance with IEC 61508 (right). Together with the SIL relays a control circuit solution can be created which is typically used in the area of functional safety for the process industries.
Intrinsically safe measuring circuit
Intrinsically safe circuits to limit energy are used in explosion risk zones. In these circuits, the intrinsically safe signal converters with their galvanic isolation and Exi approved surge arresters provide excellent protection for sensitive control electronics. Lightning strikes and overvoltages in the field on measurement and control cables can lead to explosions.
Today’s control systems are increasingly more complex with higher and higher demands for the monitoring and capturing of operational data. These demands result an increasingly large number of field measuring devices. These trends pose new challenges to engineers. On one hand, the additional signals for the automation need to be connected and processed. On the other hand, extra space in associated with increased costs. These demands are met with Weidmüller’s new marshalling and distribution terminals. The PRV, with its PUSH IN wire connection, is the most compact marshalling terminal worldwide.
The ACT20P-UI-2RCO limit value monitoring component is configured with button, display and decode switch or with the FDT/DTM software. DC voltage, temperature signals and resistance signals can be captured on the input side. The relay outputs can be freely configured. The ACT20P-UI-2RCO is galvanically isolated with 3 kV. It is connected with pluggable and coded screw connection elements. Excellent reliability and accuracy, wide operating temperature range and international approvals: this ensures that they are suitable for use in numerous applications throughout the world.
The VARITECTOR SPC is characterised by highest protective functions with compact dimensions. The arrestor of the modules can be removed or exchanged during running operation impedance-neutral – without interrupting the measuring circuit. Thus, the product is ideally suited for protecting instrumentation, control and automation circuits.
In process control systems for facilities in the process and power generation sectors, incoming signals from field devices are often connected with terminal blocks within marshalling cabinets. Terminal blocks are used despite the existence of alternative technologies such as Remote I/O and Fieldbus. This is mainly because they offer a robust and simple connection system, and are clearly arranged.Weidmüller’s new WMF (Weidmüller Multi-Functional) line of terminal blocks provides a multi-functional solution for routing and distributing signals.
Safety control circuit
About 20 % of the signals in process and energy technology are processed in safety-related applications, e.g. emergency shutdown systems. Their task is clearly defined: Immediate and automatic initiation of corrective measures – up to the shutdown of plants and plant components - in case of danger. Weidmüller’s SIL relay is particularly suitable for these tasks and applications. It has been certified by TÜV Nord in accordance with EN 61508 for the safety requirement level SIL 3.