M8 and M12 connectors are circular connectors with a 12mm mating thread (note the thread in question is the thread joining the two mating connectors together, not the other threads which may be present on the M12 connector, such as panel-mount variants which typically have a 16mm thread for mounting to the panel). They are used for a variety of purposes across a large number of industries. A large number of these connectors are rated IP67 and prevent the ingress of water and dust.
M8/M12 connectors have different codings. Each coding is a particular pin arrangement and key which prevents the same diameter and pin connector being mated with connectors with different codings.
- A: Sensors, DC power (deprecated use), 1Gbit Ethernet. This is a very common/popular encoding.
- B: PROFIBUS
- C: AC power (deprecated)
- D: 100Mbit ethernet
- K: AC power
- L: PROFINET DC power
- S: AC power (replacement for
- T: DC power (replacement for
- X: 10Gbit Ethernet
Common pin counts:
- 4 (M8, M12)
- 5 (M12, sometimes M8)
- 8 (M12)
- 12 (M12)
Some of the panel mount M12 connectors have a M16mm panel mount thead, others have a PG9 (see https://en.wikipedia.org/wiki/Panzergewinde) thread.
They typically have a PG7 or PG9 thread. The PG9 thread seems to be more common/widely available. The inline connectors may have screw termination (terminal block style).
The M8/M12 connector family also come with splitters — Y and T shaped units which allow 3 cables to be connected together.
Field Installable Connectors
Some M8/M12 connectors are stated as field installable.