Hi
I've got a Boxford 160TCL that I'm converting to use Mach3, I am using this 5 axis breakout board:
http://www.savebase.com/infobase/dow...kout_board.pdf
I'm trying to connect an optical switch to it in order to use it as an index pulse. I want to get this right before I try to figure out how to connect the VFD which is another matter entirely, I will try hooking it up directly as the BOB can output 0-10v analogue but I may wind up using a spindle breakout board anyway.
The problem I have is that the limit switch connections have 3.3v present even with nothing connected. With a test opto switch connected I get 3.4v untriggered and 3.9v triggered, Mach3 can't tell this is triggered. I'v tried to connect pull down resistors of both 22K and 220 ohm, neither of which work. I believe the problem is that the board has pullup resistors on the inputs (back of the board) but I want some help before I start snapping components off of the board.
A mechanical switch connected triggers perfectly and is recognised by Mach3.
I'm new to this stuff so speak slowly and don't use long words...
Thanks in advance
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Hi John
Thanks. I don't know much about the optical switch, it's one of a bunch I bought a while ago for my 3D printers. It's operating range is 3.3-5v but that's all I know. It has some supporting components on it's board including a very helpful LED.
https://goo.gl/images/UBNBdX
The optical switches built into the lathe (ideally the ones I want to use) seem to be working off of 12v but don't seem to trigger even when connected to the original board so I will be swapping those out for whatever I get working.
Duly noted about the lack of d-a converter, I'll start searching for a spindle breakout board. I've not had any luck so far finding one, the chap at diycnc (Roy) seems to be too busy at the moment to make one of his famed boards.
Pin 14, can I use that as an input? Mach3* and the BOB seem to both think it's a stepper output.
*Mach3 doesn't list it as an input pin on the inputs page.
only pins 10 , 11 , 12 ,13 & 15 are inputs
if you had a second parallel printer port pins 2 to 9 could be set up as either 8 inputs or 8 outputs if you have a BOB like CNC4PC's C10
looking at the photo of the photo switch you linked to
I can only see a 1000 ohm resistor that looks like the current limiter for the LED indicator so I guess there are two more some where
this is what I expect the board to be -
(assuming the LED shows when the photo transistor is on and is not a 5v power indicator )
when the photo transistor is illuminated by the LED in side the TSCT2103 the output should be between 0V and 0.7V
when the photo transistor is dark (LED's light blocked off by an opaque flag and no stray light)
the output should be over 3.5V
John
Last edited by john-100; 01-28-2018 at 06:38 PM.
Hi John
Many thanks.
There are indeed 2 more resistors on the back side of the switch.
I can't find any more switches to test to see if this one's faulty, i.e. leaking it's supply voltage through the sense wire.
Would I be better off getting something like this that seems to have an additional transistor on the board?
I'm really not sure what to do.
Thanks for all your help, I appreciate it.
EDIT:
Plan B would be to get this breakout board, it has the 0-10v output, and pray that the inputs aren't powered. For the price it could be worth a punt.
5 Axis CNC Breakout Board Interface Adapter For Stepper Motor Driver + USB Cable | eBay
EDIT EDIT:
This video suggests that the inputs on the above breakout board are not powered.
Last edited by Ishtar; 01-29-2018 at 05:50 AM.
Hi Ishtar
this link in your first post -
404 - File or directory not found.
is not the board in your last post !!!
this is the board in the video -
this board does have a PWM to analogue 10V converter for your VFD
on this BOB the LED inside of the opto-isolator is powered from a 10V regulator
a 1K resistor limits the LED current when the switch grounds the input terminal
depending on the meter you use
the BOB input open circuit voltage will be about 9 to 10 V
a simple micro switch will work OK but any electronic switch will need to have a NPN open collector output
the opto interrupter switch you have has a 2K2 resistor (in parallel with the LED indicater + 1K resistor)
between the +5V supply terminal and the NPN photo transistors collector
when the transistor is switched off , some current will flow from the BOB's +10V supply and into the opto switches +5v supply !!!
depending on the minimum current to ground the printer port needs to have to ground for a valid logic 0
mach 3 may not see the switch operate
John
Last edited by john-100; 01-29-2018 at 09:33 AM.
Hi John
Thanks, the board in my last post is an alternative I'm considering, it's not the one I have currently. The one in the first post is correct.
What do I need to do to get my original board to recognise the logic from my existing switch? Do I need to remove the 2K2 resistor on the switch?
Thanks
Hi Ishtar
sorry I missed the alert to your post
looking at the BOB & limit switch circuits you may have to remove the 2K2 resistor ( & possibly the LED or 1K resistor)
as it is ,
when the limit switches NPN photo transistor is OFF because the LED's light is blocked
there may be enough current flowing from the BOB's +10V supply via the BOB's opto-isolators LED & 1K resistor plus the limit switch 2K2 resistor to the limit switches + 5V supply
switching ON the the BOB's opto-isolator , so it will look like the limit switches photo-transistor is permanently switched ON
John
Hi John
I have a spare switch so I'll start removing components from the red switch.
I have had successful triggers by using a separate transistor but I don't think it's switching fast enough to be used as an index pulse.
The only thing to do is have a go and let you know.
Thanks
Hi John
Please may I tap into your font of knowledge once again? I have sorted the index pulse issue with a CNC4PC board, which does the same thing as my transistor but much more reliable and easier to configure.
The BOB is outputting constantly from the 0-10v, around 8.5v. I can't seem to get Mach3 to operate the 0-10v at all. I have configured it as per the manual and a few other ways too. BOB is powered by 24v and the USB port.
Thanks
Hi Ishtar
which CNC4PC board do you have ?
Hi Ishtar
now I have down loaded the ST-V2 manual
I see they set the PWM pin 1 to active Low
if my circuit diagram is correct
I would of expected pin 1 should of been set as active high !
So the output will be near 0V
so far after another disastrous windows update
its only taken me 10 days and 1.06 Tb to get back to some thing like normal
for now I will have to download the Mach 3 manual to look at the set up page for the spindle
John