- Mount the Servopack within the cabinet where it is easy to connect to the Acorn and mains power.
- Fit a sealed (female) connector on the cabinet so that I can remove the 4th axis when not in use.
- Make the connections to the encoder (signal) and motor (power) through separate screened cables running through flexible conduit to the above connector.
- The connector needs to be rated for mains voltage, as the servo power circuit is at mains potential.
- I need 4 ways for the encoder circuit and 3 ways for the motor - plus screens. Something like a 10 way connector might suffice, to allow a couple of spare pins (a loopback perhaps?).
- A quick scan of CPC, Farnell and RS suggests a circular military type connector would give a reasonable tradeoff of cost, voltage rating and robustness. There's a wide variety of circular military connectors but CPC keep some Amphenol examples:
I went for these in the end: 10 way, size 18 socket, matching 10 way size 18 free plug, backshell for the plug and some 20mm plastic conduit.
As ever, CPC are cheaper than their sister company Farnell. The Farnell connector is £19 while the identical CPC one is £12. It's often like this and makes CPC my first choice if I can find what I need in their narrower range.
The stuff turned up today. Looks up to the job. Here's what the fully assembled socket / plug / backshell looks like:
Here it is alongside a short length of the conduit and an example of the plastic glands they come with. I need to terminate the conduit to the connector somehow.
I can see a solution here. Turn down the nut so it fits in the cable clamp housing. Chop off the cable clamp parts and screw the plastic gland into the nut, now located within the metal body of the clamp. That should work reasonably well - and may even be vaguely waterproof if I fit a washer where the plastic gland meets the cable clamp body.
So - mount the (female) connector on the cabinet and wire it up to the Acorn. Wire the motor and encoder through the conduit to the free plug. Sounds simple enough. Let's do it.