Circular Connectors
Circular connectors (M8, M12, M23, and Mil-Spec 38999 series) are the workhorses of industrial cable assemblies. They offer robust mechanical coupling, good EMC shielding, and are available in IP67/IP68 rated variants for harsh environments.
M12 connectors are particularly prevalent in factory automation, with standardised coding (A-code for sensors, D-code for Ethernet, X-code for 10 Gbit Ethernet) ensuring correct mating. Always confirm the coding when specifying — an A-coded plug physically fits a D-coded socket but will not make a reliable data connection.
Rectangular and Modular Connectors
For higher pin counts or mixed signal/power requirements, rectangular connectors such as the Han series (Harting), EPIC (Lapp), or TE Heavy Duty ranges offer modular inserts that combine power, signal, data, and even pneumatic connections in a single housing.
These are ideal for machine-to-cabinet interfaces where a single-point disconnect simplifies maintenance. Specify the insert arrangement carefully — modules from different manufacturers are generally not cross-compatible even if the housing dimensions appear similar.
Board-Level Connectors
Where a cable assembly terminates directly to a PCB, common options include JST, Molex, and TE Micro-Fit ranges. Key considerations here are pitch (1.25 mm, 2.0 mm, 2.54 mm, etc.), current rating per contact, and whether a locking feature is required to prevent accidental disconnection under vibration.
For production volumes, consider wire-to-board connectors with pre-crimped leads — this reduces assembly time and eliminates solder joint reliability concerns.
Mating Cycles and Durability
Every connector has a rated number of mating cycles — the number of times it can be connected and disconnected before contact resistance increases beyond specification. Industrial circular connectors typically offer 500–1,000 cycles. USB and RJ45 connectors are rated for around 1,500–10,000 cycles.
If your application requires frequent mating (e.g. test equipment, portable medical devices), specify a connector family with a higher cycle rating and consider gold-plated contacts for consistent low-resistance connections.