Signal interfacing need not be a bind
In many sectors, selecting the correct interfacing relay is one of many frustrations, along with limited space on the mounting rail when there is a need for a smaller electrical cabinet layout.
Traditional methods of isolating a variety of signals of different voltages emanating from the field can also be time consuming and create costly onsite conversion work. In retrofitting in the process industry, for example, relay modules are generally being taken from the workshop and installed in a tested electrical cabinet and this requires the maintenance personnel to carry a range of products to suit each individual applications.
The machine building industry is another example where there is the need to condition a variety of signals of different voltages in production lines; signals are transferred between the machine and handling system. These signals can be in the form of an output from the control cabinet to the handling system to, for example, start or stop a conveyor belt, or they can be in the form of an input from the handling system to alert the control system of an error. This can result in a range of control voltages being present, requiring a large number of interface units.
It is for reasons such as these that users have stated that they wish to simplify the selection of interface relays. Choosing a multi-voltage input allows signals from 24-230V AC/DC to be conditioned with just a single module. This reduces storage costs and makes it possible to implement a universal connection to the field level.
Users have also stated that they wish to see high component density solutions for smaller electrical cabinet layouts, professional handling and comprehensive equipment identification options implemented in future oriented connection levels. To satisfy these demands, users can now select from a new range of slim line relay modules and solid state relays. With a choice of one or two changeover contacts, the modules are housed in slim line widths of 6.4mm and 12.8mm. Not only does this save space on the mounting rail, but it also makes it possible to plan and implement smaller electrical cabinets.
The Termseries from Weidmuller offers high performance relay modules and solid-state relays that can be combined as required, and reliably switch loads of up to 8A at 250V. Relay modules are also available with gold contacts for switching low power loads. The range also includes pluggable solid-state relays for applications in which reliability and freedom from wear are important. Users can take full advantage of the fact that the pluggable modules are easily exchanged or replaced during maintenance procedures, without having to undertake the time consuming task of disconnecting wiring.
The modules are available with a choice of screw or tension clamp connection technologies. The housing design ensures equipment markings are always clearly visible and colour coding differentiates different voltage versions. A double-sided printing option ensures markings are always easy to read in different mounted positions. Colour coding at the top of the modules indicates the voltage type to reduce wiring errors; blue is for DC, red for AC and white for UC (AC/DC).
In addition, there are red partition plates to electrically isolate component assemblies or serve to create groups. It is also easy to fit a large number of markers to all partitions (marker types WAD5) to help identify groups. Further distinguishing features of the Termseries include a wide range of versions to suit different applications. All relay modules and solid-state relays have matching contours and a universal cross-connection solution, including across partition plates. It is even possible to cross-connect screw and tension clamp versions. Users are able to cross-connect between all product versions across all five connection levels; a design feature that considerably reduces wiring times. With pre-marked break points it is particularly easy to shorten the cross-connectors to the required length.
The cross-connectors are provided with a safe handling element to ensure that users do not need to touch the contacts. The LED serves as a status indicator and also illuminates the complete ejection lever so that even in installation conditions where visibility is an issue, visible indication is assured. The ejection lever ensures it is possible to remove the switching element safely with a clearly audible 'click' indicating when the relay or solid-state module has securely snapped into position. All edges of the modules are rounded to facilitate easy installation; a design feature that simplifies securing numerous modules onto the mounting rail.
Peter Croucher, Product Manager at Weidmuller UK
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