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Parallel Cable Woes
« on: August 01, 2008, 10:36:22 AM »
New to CNC but managed to get up and running until I went to set up limit switches but before I go there, let me explain that I'm suspicious of the cable I am using and would like to hear what I should be seeing on the Diagnostics screen under Port 1 Pins Current State.

With one so called parallel Cable I get lights 1 2 3 and 5 lit up with the rest off (reading from left to right). My motors turn accurately but when I connect a switch to Pin 10 and to common and press it, it doesn't light up.

So I went to Radio Shack and bought something called a Parallel MS/DOS Interlink Cable and now I get lights 1 thru 8 lit with the rest off but motors won't turn never mind the switches.

Please help.

Al

Offline Hood

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Re: Parallel Cable Woes
« Reply #1 on: August 01, 2008, 10:47:14 AM »
Easiest thing do do if you have a meter is set it to Ohm range or continuity test if it has one. Check pin to pin on the cable to make sure there are no crossover wires as some cables are crossover rather than straight through.
 
Hood
Re: Parallel Cable Woes
« Reply #2 on: August 01, 2008, 03:40:28 PM »
I checked all three of my cables and found only one "good" one ie. continuity on all pins. So that's ons thing out of the way.

Now on to my LPT1 port (JPG attached) Although it does use 378 it also shows 778. Is this a problem?

When I attach a switch to Pin 10, Port 1 and enable it, the diagmostic screen can't "see" it. If I check the active low it lights up but pressing the switch does nothing. I checked the switch for continuity and it is OK.

Very frustrating indeed

Al

Offline Hood

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Re: Parallel Cable Woes
« Reply #3 on: August 01, 2008, 03:49:52 PM »
378 is the address you use.
Have you set it up in Ports and pins to have the limit on the port and pin and remembered to enable it?
If so and you are not seeing the LED for limits lighting then there is either a fault in your port(not really likely) or there is a problem further out. How are you connecting to the cable, are you using a breakout board? If so what kind? Can you try another pin?
Hood
Re: Parallel Cable Woes
« Reply #4 on: August 03, 2008, 08:12:37 AM »
Yes, have set up port & Pin and enabled it. Now checking with Patrick at "Buildyourcnc" to see if I understood how to connect to BOB correctly. Will advise.

Al

Offline jimpinder

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Re: Parallel Cable Woes
« Reply #5 on: August 03, 2008, 10:33:24 AM »
The purpose of the led display is a little confusing. What it displays is whether the computer sees an "active" signal on the pin, or not. (Not if the computer is seeing a +5v or not)
If in your case, the led lights when an "active low" is ticked means that the computer sees a low on the pin and says, that is active, and lights the led.

The normal state of the 5 input pins in the computer is +5v, because the computer is fitted with internal pull up resistors. This means that your BOB is putting a negative signal to the pin. Try the others and you will probably find that all the others are "active" on "active low" as well. This means that your BOB is reversing the signal to the computer.

A lot of the boards do this, and it is very confusing. What board is it.
Not me driving the engine - I'm better looking.
Re: Parallel Cable Woes
« Reply #6 on: August 04, 2008, 06:43:19 AM »
My BOB is a CNC4PC board model C10.
You can set pins 2 thru 9 as input or output, mine is set to output and you can set the 2 thru 9 common pins as ground or 5vdc, mine is set to ground.
The tutorial video instructs one to connect the switch to #10 and to common. (I tried this with 10 & 11 with same results ie no recognition whatsoever). BTY the connections to the switch are to the NC post and the C post.

Al

Offline Hood

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Re: Parallel Cable Woes
« Reply #7 on: August 04, 2008, 06:48:48 AM »
I had a sneaking suspicion that it may be, seems to have been a few similar problems lately with the CNC4PC BOBs. Have you been in touch with Arturo to see what he says?

Hood
Re: Parallel Cable Woes
« Reply #8 on: August 09, 2008, 04:16:21 PM »
Hi Hood,

Sorry, I missed this post until today. No, I haven't contacted Arturo but will send of a note to see what he has to say.

Tks

Al
Re: Parallel Cable Woes
« Reply #9 on: August 12, 2008, 10:38:02 AM »
Hi Hood, This is what I sent to Arturo and his reply.

From: Al McLellan [mailto:lady@muskoka.com]
Sent: Saturday, August 09, 2008 3:39 PM
To: Arturo Duncan
Subject: Enquiry from CNC4PC

 

Hi,

I am trying to set up my limit and home switches using your CNC4PC C10 board and having problems.

Board jumpers are as they were from the factory, ie. pins 2-9 set as output and 2-9 common set to Ground.

When I hook switch up to Pin 10 (or 11 or 12) and the other wire to any of the 2-9 commons and set the port and pins in Mach3 to "enable" the program doesn't react in any way. ie No lights in the diagnostic screen.

However, if I hook up the switch up to pin 10 and then to any og the 5v sources, the switch is recognized but it physically doesn't stop the motor.

Tried all of the forums but no luck. Am I missing something.

Al

He replies as follows:

Al,

 

Sorry for the delay in getting to you.  I was taking a couple of days off.

 

You have to go to: Config / Ports&Pins / Input Pins.  There you have to assign the pins.

 

Have you done this before?

 

Is everything else working ok?

 

Thanks,

 

Arturo Duncan

As you can see, he missed the text where I said I "enabled" the ports and Pins and said nothing really. So I wrote back the following:


Hi,
 
I think I have it figured it out now. When I connect to pin # 10 and to 5v not ground and put a check in the active low box everything works. ie. when the switch is closed, the motor stops.
 
Originally, I was led to believe pin # 10 was supposed to be connected to ground!
 
Thanks
 
Al

He replied as follows:

Al,

 

I am glad all is fine now.

 

Thanks for letting me know.



OK, so I said I got it working in some manner but it's still not right according to the Mach3 set up video and I still don't know what's wrong.
I can get the machine to "Ref All Home" under this 5v scenerio, but it won't back off the "Z" switch unless I disable it and jog off then when I "Ref All Home" again, it homes the "Y"
but won't back off etc. as above.

At this point I'm ready to give up on limit and home switches but I realize this is foolish and would like to figure it out once and for all.

The funny thing is that I have the router working beautifully with mach3 and lazycam.

Can you come up with anything that might get me out of this delima?

BTW, Thanks for all your efforts thus far. I do appreciate it and realize this is a volunteered service with little reward other
than the satisfaction gained when you actually get a fellow CNC'er up and running.

Let's give it one last try.

Al