Closed Loop Stepper Encoder Wiring

[Cncninja]

If the cabinet is permanently affixed to the machine then direct pass threw is reasonable and preferred. But the Acorn comes with a DB25 G540 compatible plug. which, in turn, uses DB9's, etc. So a lot of smaller DIY build not based on a retrofit may have a separate control box where connectors make sense. So every use case is different, a properly shielded connector needs to be used and the shield connected to the housing ( I've seen so many not connected). So best practice would be Shielded all the way if possible, if a connector is needed make sure it has a shielded housing and is connected to the wire shield, If the wire shielding must be cut back due to different connection points in a multi-strand cable use shielding tap to finish it. Wire separation cross vs parallel routing and the use of chokes/ferrite rings and optocouplers. Also, set up inputs to be pulled low for triggering so transit noise does not trip a false input, try and get Debounce low.

[martyscncgarage]

Greglwood,
Do you have an Acorn or just doing some researching?

[greglwood]

For the record my question was about cabling vs wires from connector to the driver for both the encoder and power. The existing ones (power) are temporary , I've already removed the encoder wires. I've seen lots of these done as I have the power wires here but that does not mean its the best way. Should they be shielded together (all encoder) or a+/a- shielded together, b+/b- shielded together, etc. Same raceway or different raceways (power and signals).

[martyscncgarage]

For the record my question was about cabling vs wires from connector to the driver for both the encoder and power. The existing ones (power) are temporary , I've already removed the encoder wires. I've seen lots of these done as I have the power wires here but that does not mean its the best way. Should they be shielded together (all encoder) or a+/a- shielded together, b+/b- shielded together, etc. Same raceway or different raceways (power and signals).

IMG_4478.JPEG

In general it looks neat. I do not see your drives. Are they stepper drives? What make and model? 5VDC Logic? If so they should be connected to the DB25 port. SOME work on the acorn header. I would have used a shielded cable for the step/dir signals from the Acorn to each drive.

Is this a mill? Router? What kind of spindle and how is it controlled?

More pictures would be helpful, We can make more suggestions

[greglwood]

Greglwood,
Do you have an Acorn or just doing some researching?

I have an acorn, eth1616, and wireless MPG. Everything is/was working just fine, but I desire to clean up the cabling. I know people on here have already said don't use a connector and go directly to drivers but in my mind that is just asking for problems. Hang one cable on your foot and tear up who knows what on the inside of your enclosure. I don't build panels but I have programmed PLC for 30+ years and been in dozens of factories. You would never just run a cable thru an open hole and connect it to something on the inside.

This is for my own home use but I want everything tidy, tied down and easy to disconnect and move; as I often have to rearrange my shop when say "I buy that new lathe to convert to cnc" or "build a 9x5 cnc router" (lol).

[martyscncgarage]

Greglwood,
Do you have an Acorn or just doing some researching?

I have an acorn, eth1616, and wireless MPG. Everything is/was working just fine, but I desire to clean up the cabling. I know people on here have already said don't use a connector and go directly to drivers but in my mind that is just asking for problems. Hang one cable on your foot and tear up who knows what on the inside of your enclosure. I don't build panels but I have programmed PLC for 30+ years and been in dozens of factories. You would never just run a cable thru an open hole and connect it to something on the inside.

This is for my own home use but I want everything tidy, tied down and easy to disconnect and move; as I often have to rearrange my shop when say "I buy that new lathe to convert to cnc" or "build a 9x5 cnc router" (lol).

If you want to connectorize your cables and use bulkhead connectors you certainly may.
I have built most controls without them, using a STRAIN RELIEF as it enters the cabinet and certainly you need to use cable carriers where possible in order to keep cables up off the floor where they might get caught.

The types of connectors you use would be up to you. If its an encoder cable, make sure the cable is shielded as is the bulkhead connector.
You CAN get Shielded RJ45 Ethernet bulkhead connectors from Amazon.
You can use the inexpensive "aircraft" 4 pin connectors for motor power.

It is NOT uncommon NOT to have a connector on cables entering a cabinet I use Centroid's cable strain relief on nearly all my builds and I cut them in half for smaller builds. Can be found here toward the bottom of the page:
https://www.centroidcnc.com/centroid_di ... nents.html

These work well for things like limit switches, estop buttons etc. and can be had in multiple pin configurations.
https://www.mdfly.com/products/hq-10-pi ... mount.html

I have used a regular receptacle on the side of the cabinet for a router motor, vacuum, dust collector (provided the device does not exceed the outlet rating)

Then there is the MS (Military Spec) connectors which you probably have seen on machines. They are good, but they are expensive.
CPC connectors (Circular Plastic Connector) are also popular and less expensive. You can find those that use DB9 crimp pins. Most have a mating bulkhead connector. Centroid uses them on their Probe Bulkhead connector.

You can also use a Panel mount DB connector.

Just remember you are adding twice the terminations every time you add a connector so you need to make sure you have the skills to properly terminate them.

Marty

[ShawnM]

Of course you don't run a cable through an open, always use a cable gland or some type of strain relief. I thought that was a given.

Encoder cables are shielded, twisted pair if you want best practice. Step/direction wires are also shielded wires. For me this means from the moment it leaves the controller until it's terminated. The shields on those wires are then grounded at one end to your PE bus bar. I've seen many systems where people use plain old copper wire inside the cabinet to a connector on the cabinet and then use nice shielded wire until it's terminated. Many left ungrounded. The noisiest place in the system is inside the cabinet, wouldn't you want good, shielded wire in here?

You asked for "best practice" and I think many have given you that info and I don't think anyone "scolded" you at all. You'll learn that if you ask a question on here you'll get many, many answers and then you can make the best decision for you.

[greglwood]

more info needed...drive make model and link to manual for starters....typically you would buy encoder cables from the drive manufacture when using a closed loop stepper drive or ac servo drive.. are you building your own? yes encoder cables should have a drain and a shield and use twisted pair wires.

WOW! I was not expecting to get scolded for trying to start a philosophical conversation about best practices. My post was not a cry for help nor did I give any indication that I was having a problem getting anything to work. I prescribe to the old adage of “An oz of prevention is work a pound of cure”.

Is this forum help only, no generic discussions allowed? If so I do apologize, I will post this over on the cnc machinist forum.

We assumed that you were looking for support. Your initial post was not clear that in general, you were looking for best practices.
No one is scolding you. We get so many requests for help with little information from the poster, that we have to try and dig for more information in order to provide good useful suggestions.

I believe I did provide a few tips in respect to what you were asking.

Marty

Thanks for the response. In my own defense I would like to point out my first sentence was "I am interest in best practices...". But admittedly I'm a guy who had all A's in math and science but D's in English and Literature and as such does a very bad job of expressing myself with the written word.

[Cncninja]

For the record my question was about cabling vs wires from connector to the driver for both the encoder and power. The existing ones (power) are temporary , I've already removed the encoder wires. I've seen lots of these done as I have the power wires here but that does not mean its the best way. Should they be shielded together (all encoder) or a+/a- shielded together, b+/b- shielded together, etc. Same raceway or different raceways (power and signals).

IMG_4478.JPEG

In general it looks neat. I do not see your drives. Are they stepper drives? What make and model? 5VDC Logic? If so they should be connected to the DB25 port. SOME work on the acorn header. I would have used a shielded cable for the step/dir signals from the Acorn to each drive.

Is this a mill? Router? What kind of spindle and how is it controlled?

More pictures would be helpful, We can make more suggestions

Hey Marty is the DB25 electrical the same as the headers or is there different paths, optos, levels etc I have not yet terminated mine yet so I could easily use a DB25 bob or even a CNC pin-compatible Gecko bob with opto. Thanks

[ShawnM]

If the cabinet is permanently affixed to the machine then direct pass threw is reasonable and preferred. But the Acorn comes with a DB25 G540 compatible plug. which, in turn, uses DB9's, etc. So a lot of smaller DIY build not based on a retrofit may have a separate control box where connectors make sense. So every use case is different, a properly shielded connector needs to be used and the shield connected to the housing ( I've seen so many not connected). So best practice would be Shielded all the way if possible, if a connector is needed make sure it has a shielded housing and is connected to the wire shield, If the wire shielding must be cut back due to different connection points in a multi-strand cable use shielding tap to finish it. Wire separation cross vs parallel routing and the use of chokes/ferrite rings and optocouplers. Also, set up inputs to be pulled low for triggering so transit noise does not trip a false input, try and get Debounce low.

I agree with you on your wiring practices and every build is certainly different as is the skill level and knowledge of those building them. We all had to start somewhere and learn this stuff somehow.

All the industrial machines I refer to have a separate control cabinet that is usually connected with several, large, 2-3 inch plastic conduit hoses. No connectors are used between the control cabinet and the machine. Wires are terminated at each device they run to with no way to disconnect them anywhere along the run. I can share some pics if you like.

Of course in the hobby world many people use all sorts of connectors and it's perfectly ok if that's what one chooses to do. As Marty stated every time you add a connector you add in twice as much work. In addition to that, I feel that you are also introducing another failure point. I find it "best practice" not to induce any additional failure points, no?