RCG and RDG Forceguided Relays Advance Industrial Safety
Industrial control systems operating in demanding environments require switching components that guarantee both electrical continuity and verifiable safety logic. The RCG and RDG series of forced-guided relays are designed to meet that requirement, combining mechanically linked contacts with a structure that conforms to EN 61810-3 type A classification. The following assessment outlines the technical basis of the design, the available product families and their principal performance characteristics.
Forced-guided contacts as a safety mechanism
Forced-guided, or mechanically linked, contacts are a central component in raising the safety integrity of industrial control systems. The RCG and RDG series conform to the EN 61810-3 standard and are classified as type A relays, meaning that all contacts are mechanically linked and therefore governed by the no-weld-transfer principle.
In self-monitoring control systems, continuous observation of contact status allows the system to determine with certainty the condition of the remaining contacts inside the relay. This arrangement prevents false operation caused by welded or stuck contacts, a common failure mode in conventional relay designs.
The result is a switching element whose behaviour can be monitored rather than merely assumed, a distinction that matters in applications where an undetected contact failure could compromise the wider safety circuit.
Product families and selection reference
The range is organised into several families, each oriented toward a different balance of switching density, service life and diagnostic capability. All share the same type A mechanical linkage principle under the EN 61810-3 framework.
| Series | Principal characteristics | Standard compliance |
|---|---|---|
| RCG / RDG series | High reliability, suited to demanding interference environments | EN 61810-3 type A |
| RGG series | Heavy-duty and high-density tasks, extended service life | EN 61810-3 type A |
| RMGX series | Eight forced-guided contacts, manual test facility | IEC EN 61810-3 type A |
Switching performance and mechanical design
The RCG and RDG series are engineered for complex operating conditions. Their contacts offer substantial breaking capacity, allowing them to handle high inductive loads as well as high-frequency switching at very low loads. An optional magnetic arc-suppression feature further reinforces breaking performance.
A knurled contact design provides a self-cleaning effect and reduces ohmic resistance, extending the electrical service life of the component. The mechanical linkage also imposes a defined physical relationship between normally open (NO) and normally closed (NC) contacts, which cannot occupy the same state simultaneously.
Contact gap logic
When the relay is energised, if an NC contact fails to open, the NO contacts are forced to maintain a contact gap of at least 0.5 mm. Conversely, in the de-energised state, if an NO contact fails to open, the NC contacts likewise maintain a gap of at least 0.5 mm. The arrangement excludes unsafe states through physical structure rather than electronic supervision alone.
