Newbie- Wiring Home switches to a 9 Pin D Sub (struggling to interpret instructions)

[craigspc]

Hello everyone,

I recently bought a pre-assembled cnc router, which I am trying to hook up to a controller/driver that I purchased seperately. The controller uses 9 Pin D-Sub connectors for the motors, and also has a 9 pin connector, which can be used for home switches etc.

Being a novice with electronics, I'm very frightened of making a mistake, which could cause damage to my equipment. Would anyone be kind enough to help me?

As you can see from the following image, I've managed to wire up the plugs for the motors (which I am proud to say work perfectly!). However, I'm confused about how I should wire up the 3 home switches. The switches are connected to the loose wires that you can see in the bottom left hand side of the image..







The router came with a document that shows a recommended method for connecting the switches. Here's a copy that I scanned in:







The controller that I purchased has a 9 pin D-SUB connector for these switches. Here's a copy of the instructions for the controller







I guess that the wires, which the router instructions suggest should be connected to pins 11, 12 and 13 on the parallel port, should be connected to pins 1, 2 and 3 on the 9 pin D-Sub plug (?). If this is correct though, what do I do with the other three wires that all need to go to pin 25 on the parallel port?



If it helps, here's a picture of one of the three switches fitted to my router.







Finally (and I hope I'm not asking too much here here), I have a question, which is less important to me than getting the machine up and running, but does cause me a great deal of confusion...

My last cnc machine (a small pre-converted proxxon MF70 milling machine) appeared to have all home switches operating from a single parallel port pin. The machine seemed to work fine using just one pin, so I'm confused about why this machine needs to use 3 pins to achieve the same effect. Can anyone help clarify this for me as I'm starting to drown in confusion


Many thanks to anyone that is willing to help me.

Best regards,
Craig.

[Al_The_Man]

If you want to wire three switches up to one input, two ways are either all normally open in parallel (OR function) , or all Normally closed in series (AND function).
Your pic shows three switches to different inputs, so these can be differentiated by software, if you use the series/parallel and/or connection, any one switch cannot be identified.
Pin 18-25 of the parallel port is usually P.S. common.
Al.

[craigspc]

Thanks for your reply, Al.

I think I follow what you're saying. I noticed that with my old machine (using Mach3), the system would first home the Z axis, then the Y axis, then finally the X Axis. I guess that if all switches were working via one pin on the parallel port, the software could determine which axis the switch referred to, based on the order in which it homed each axis. Is that a reasonable summary?

Although I THINK that I can follow this logic in theory, I still have no clue as to how this works in terms of connecting up the wires (I really am a complete novice). That being the case, it's probably best if I stick to the recommended wiring method until I have a little more knowledge.

This brings me back to the first part of my question about the 3 wires that go to pin 25 on my router's instruction diagram. You mentioned that pins 18-25 are usually 'P.S common', but I must admit that I don't know what the term "P.S Common" means. Worse still, if none of the pins on the controller's 9 pin plug are forwarded to pins 18-25 of the parallel port, how can I hook up the home switches on this machine?

Assuming that it is possible to wire up the switches for my equipment, would anyone be able to give me a simple explanation of which wires I should solder to which pins? All I really understand from the wiring side is that I have 6 loose wires (2 from each switch), each of which need to be connected to one of 9 pins on a 9 Pin D-SUB plug.

As you can probably see by now, I'm a bit thick :-(

Best regards,
Craig.

[Oldmanandhistoy]

Originally Posted by craigspc I guess that the wires, which the router instructions suggest should be connected to pins 11, 12 and 13 on the parallel port, should be connected to pins 1, 2 and 3 on the 9 pin D-Sub plug (?). If this is correct though, what do I do with the other three wires that all need to go to pin 25 on the parallel port?

You guess correct

The other three wires go to pin # 7,8 and 9 of your D-sub plug which are all ground.

John

[craigspc]

Originally Posted by Oldmanandhistoy You guess correct The other three wires go to pin # 7,8 and 9 of your D-sub plug which are all ground. John

Thanks John. It's working now. Strange that I've never heard of the term "P.S Common" before though. Is it a universally understood meaning for "Earth" or "Ground" wire? Or is it an American English word? I've never seen it in any book or reference material before.

Of course, it'll be rather embarrassing for me if somebody turns round and points out that it's a British English term

Tnx again,
Craig.

[Al_The_Man]

Originally Posted by craigspc Strange that I've never heard of the term "P.S Common" before though. Is it a universally understood meaning for "Earth" or "Ground" wire? Or is it an American English word? I've never seen it in any book or reference material before. Craig.

P.S. is abbreviation for Power Supply.
Supply common is a bit more precise than Earth or Ground, as the P.S. common may, or may not, be connected to earth ground.
Al.

[craigspc]

Originally Posted by Al_The_Man P.S. is abbreviation for Power Supply. Supply common is a bit more precise than Earth or Ground, as the P.S. common may, or may not, be connected to earth ground. Al.

Thanks for the clarification.

Craig.

[ViperTX]

The other thing to check are you suppose to be using NO or NC for your switch connections.