Choosing a connector comes down to five decisions. Get these right and the connector fits, seals and lasts. Get one wrong and you’re chasing intermittent faults later. Here’s the order we tell our own customers to work through.
1. Poles and current
Count your conductors first. Signal-only devices need 3 or 4 poles; a device with power and signal might need 8 or 12. Then check current: an A-coded M12 carries 4 A, an M8 carries 3 A, and if you need 16 A you’re into L-coded M12 or heavy-duty territory. Pick the smallest connector that meets both – oversizing costs money for nothing.
2. Environment and IP rating
IP65 keeps out dust and low-pressure water jets. IP67 survives temporary immersion. IP68 handles continuous immersion. IP69K handles high-pressure, high-temperature washdown. For a normal plant floor, IP67 is the default; for food and beverage washdown, go IP69K.
3. Coding
Coding stops you from plugging the wrong cable into the wrong port. A-coded is sensors and power, D-coded is 100 Mbps Ethernet, X-coded is 10 Gbps, L-coded is power. Codes are not interchangeable, so match the code to the signal.
4. Locking
Screw-lock handles vibration and is the default for machinery. Bayonet or push-pull suits areas where operators connect and disconnect often. Snap-in suits fast machine assembly. If the connector is on a moving axis, screw-lock is the safe choice.
5. Termination
Field-wireable connectors are for one-off builds and retrofits where cable length isn’t fixed. Overmoulded pigtails suit production where every length is known. Crimp contacts are faster to assemble than screw once the tooling is set up.
A quick decision table
| Your need | Connector |
|---|---|
| Sensor or actuator, up to 4 A | M12 A-coded |
| Compact sensor, tight space | M8 |
| 100 Mbps Ethernet / PROFINET | M12 D-coded |
| 10 Gbps / machine vision | M12 X-coded |
| 16 A power distribution | M12 L-coded |
| Servo motor, signal + power | M23 |
| Cabinet power, 16 A – 100 A | Heavy-duty rectangular |
Still unsure? Send the application details and we’ll recommend the exact part, usually within a day.