12-pin M8 mating face is now standardised as C-coding

The development was triggered by a specific customer requirement: a manufacturer of length measuring systems needed more than eight signals for a new generation of devices but, for technical reasons, could not increase the M8 size it had been using. binder recognised the potential and decided to develop a 12-pin M8 mating face and add it to its standard portfolio as a separate coding.

A design challenge with an unusual solution

Twelve contacts on an M8 diameter sounds simple, but it was not. The original plan was a single, larger coding key, as used by other M8 codings. With twelve symmetrically arranged contacts, however, there was no longer room for it. The solution: five small coding keys instead of one large one. They allow the free connector to be oriented securely without bending the contacts, which are only 0.5 millimetres thin, during mating.

The format also called for precision in production. The M8 plastic bodies are fitted with the twelve contacts by hand, which requires a delicate touch and magnifying aids. The panel mount connectors use twelve fine single wires in different colours, arranged in a precisely defined order. A colour template shows employees which wire belongs in which position. The cable connectors are then moulded by machine.

Planning certainty for users

For users, standardisation means one thing above all: planning certainty. The mating face, coding and connection dimensions are now documented independently of the manufacturer. C-coding is therefore no longer a proprietary format, but a regular part of the M8 world alongside the established A and D codings. For binder customers, nothing changes technically: the products remain available as before, now backed by the standard.

C-coding has been in use in the field since 2020 - including in length measuring systems from leading manufacturers, in laboratory automation for environmental analysis and in industrial cameras from well-known manufacturers. A typical example from conveyor technology illustrates the principle: in a parcel sorting system, four sensor signals, four actuator signals and four additional signals can be routed through a single M8-C interface - turning the 12-pin M8 into a compact interface between field device and decentralised I/O level.

"With the revised standard, the foundation has been laid for consistent mating compatibility across the connector market," says Guido Werner, Product Manager at binder. "The future of automation lies, among other things, in miniaturisation, and with our portfolio of smaller sizes such as M5 and M8, we are already very well positioned for this."

With standardisation, a binder development becomes an industry standard. Users get a 12-pin interface in the compact M8 format that has been proven in the field for six years and is now documented independently of the manufacturer. binder supplies it as male and female cable connectors and as panel mount connectors for rear panel mounting.