Thread: Anyone knows how to do this?

Normally, you would simply identify the pin-outs used at each end and solder/connect pins on the appropriate plus/sockets types to each other.

Sourcing a suitable DB25 connector is not an issue, but finding a centronics socket suitable for a soldered cable (not a chassis-mount or insulation displacement cable fitting) might be problematic. I'm sure they are out there but I personally haven't seen one for decades.

There is a remote (very remote) chance I have one or two in a box in a cupboard and you are welcome to it if that's the case but who knows just now. I'll look tomorrow.

A parallel cable would typically use about 20-25 wires (can't remember right now), running from one end to the other. Sometimes pins would be simply not connected at all, or even cross-connected at one end or other to fool either the computer or controlled device into thinking all is well (like the paper-out or autofeed - a CNC won't use these in their intended role).

However, you have suggested that only 12 wires are involved and that 12 sets on 2 pin-outs are joined or cross-connected. The pairings you mention are at odds with my understanding on a 36-pin parallel port or any data port. (For instance pins 2 to 9 are data signals on a std 36pin parallel port and not joined to each other.) Where did you source the pin-out info in your post and did it name the pins ? You can't consider replacing the connector on the CNC with a more common type without knowing what to connect where.

Knowing the signal "attached" to each pin is the key. Once you have the plugs and sockets - the rest is just soldering.

I copied them straight from the plug.
CNC Plug.jpg
I have worked out that I probably need these
36PinConnector.png
They are available on ebay for a song
The pin configurations are from the so-called English manual
PinConfiguration.png
I guess the other pins are for the 4th axis which is not mentioned at all

Where and what is the 36 pin Centronics plug meant to plug in to?

Where are the wires coming from?

With the machine I received a cable with a 36 pin centronics plug in either end.
It is supposed to plug into the control box and the other end into the PC.
I was just talking to the computer guy who sold me the older PC this morning and he told me I would not find a computer with this plug installed.
He gave me a moulded cable with a 36 pin centronics in one end and a 25 db in the other end.
I just hope it works.

As always, I'm confused

You say the machine has a male Centronics port, but such ports are normally female on the device, and similarly, db25->Centronics cables are commonly designed for printers, which again, have (or at least, used to have) female Centronics ports. A male db25 to female Centronics cable would be pretty exotic.

Also, db25->Centronics cables are normally wired to single pins on the Centronics end, not pairs of pins as in your case. This page shows how the pins correspond between the two connectors:
Parallal Port DB-25 for PC interfacing - Telecommunication and Electronics Projects

Male connection as in cable not as in ports.
"With the machine I received a cable with a 36 pin centronics plug in either end.
It is supposed to plug into the control box and the other end into the PC"
Both ends are supposed to be attached with a clip not with screws as in a db25.
I believe it is called IEEE.
Too late to check the pins in the box tonight so that is on the agenda for tomorrow morning.
I am just as confused, because I was told today that the cable is not supposed to have the IEEE plug at both ends as there is no IEEE port on a PC only on an old printer.

I'm assuming that the CNC controller has this Centronics/IEEE connector on it?
If so, we need to know which pins connect to which function in the controller so we can determine which pins to use on the DB25 connector.

Do you have a photograph of the controller/connector?

That sort of Centronics plug has not been used for about 15 to 20 years. No modern computers have a Centronics port on them.
Complain to the makers and ask them why they have supplied you with ancient technology.

Originally Posted by Bob Willson

That sort of Centronics plug has not been used for about 15 to 20 years. No modern computers have a Centronics port on them.
Complain to the makers and ask them why they have supplied you with ancient technology.

Already done and not very nicely either

Tried to connect the cable I got yesterday.
BANG
Triggered the circuit breaker and blew up the new old PC and the control box

Sorry to hear that saisay.
Without some sort of a circuit diagram it is next to impossible to advise you.
I doubt that the loss of the control box is that great a loss as most of them seem to be faulty anyway. The computer on the other hand is a big loss, this is regardless of the fact that it only cost you a ticket, because the next one you buy will cost a lot more.
It would seem to likely that you will need to cut your losses at this point and go straight to a Gecko G540 controller.

Originally Posted by Bob Willson

Sorry to hear that saisay.
Without some sort of a circuit diagram it is next to impossible to advise you.
When I asked for one the answer was "Sorry we don't have one!" Wonder how they put the thing together without a diagram. One of the PCBs was just held to the wires with zip ties
I doubt that the loss of the control box is that great a loss as most of them seem to be faulty anyway. The computer on the other hand is a big loss, this is regardless of the fact that it only cost you a ticket, because the next one you buy will cost a lot more.
It would seem to likely that you will need to cut your losses at this point and go straight to a Gecko G540 controller.

Looks like a gecko to me as well, are they easy to install?

Originally Posted by SAISAY

Looks like a gecko to me as well, are they easy to install?

Very. The most you will need to do is possibly solder a few wires on, and Peter has a special PC board in a backshell to make that easier as well. Or if that is still too difficult, then he also has this.

Originally Posted by SAISAY

Tried to connect the cable I got yesterday.
BANG
Triggered the circuit breaker and blew up the new old PC and the control box

Just to clarify, you connected your PC to the engraver control box with a db25->Centronics cable, a cable which, if connected to the printer port on the PC carries TTL signals of 0 to 5 volts, and when you did so, both the PC and control box blew up and you tripped the mains breaker.

I've got to say, I'm at a complete loss as to how all those things could happen.

However, thinking further, that shot of the back of the Centronics connector in your very first post does raise some questions - you don't need 4 wires per axis to interface to a stepper controller, you only need 2, step and direction. What might require 4 wires are the steppers themselves, if they're bipolar types, which makes me think that perhaps you connected the printer port of the computer to the stepper output of the control box, and yes, some fireworks would ensue.

Some more photos of the unit you have, and maybe a link to where you got it from might help, particularly to make sure you don't blow up the Gecko drive if you go that route.