Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: BIGWING on June 01, 2011, 06:12:48 AM

Title: 8 position lathe toolchanger
Post by: BIGWING on June 01, 2011, 06:12:48 AM
Hi all

I am in the early stage of converting  an Emcoturn 120
to Mach control and at the moment I am looking at the toolchanger
it appears to be a really well made bit of kit (see photos)

It is a pawl design with a spring loaded pin used for location
meaning it can only rotate in one direction ( although the manual I
have says it can move either direction but I cant see any method for
retracting pin so I think it may be for a later version unless someone
out there can put me right) The turret position is controlled by 4 sensors
and cutaway vane which produces 4 output signals shown in the table.
Movement is via a small dc motor controlled by an emco board.

It is my intention to change the dc motor with a stepper and have a fast
rotate followed by a slow reversed rotate to lock pin as I have seen a
macro on the forum to tackle this type of setup. I have also seen another
macro setup to handle pin position input. (with if possible including the
option of a manual selector or rotate switch)

I have some user experience of mach3 mill but none of mach3 turn
and this if my first venture into the nuts and bolts of system setup.

I would like to be able to either modify existing programs or write
new to suit but dont have any knowledge of vb script .Can anyone
out there tell where I can find list of commands and construction rules
or recommend a book. As this is a skill I would love to master.

Also I am  a bit lost at the moment on how to convert the sensor
output results (see table) so mach knows that for example
1011 is position 5

any help would be greatly appreciated

cheers George
Title: Re: 8 position lathe toolchanger
Post by: Tweakie.CNC on June 01, 2011, 07:47:53 AM
The Visual Basic version used is Cypress Enable and the commands and syntax in PDF format can be downloaded from here;

http://www.machsupport.com/forum/index.php?action=dlattach;topic=18062.0;attach=26020

Also Scott's Mach specific routines here;

http://www.machsupport.com/forum/index.php?action=dlattach;topic=11056.0;attach=14194

http://www.machsupport.com/forum/index.php?action=dlattach;topic=11061.0;attach=14193

Hope this helps,

Tweakie.
Title: Re: 8 position lathe toolchanger
Post by: BIGWING on June 01, 2011, 08:40:36 AM
thanks Tweakie thats exactly what I was looking for.

now the learning curve begins

cheers george
Title: Re: 8 position lathe toolchanger
Post by: BR549 on June 01, 2011, 10:36:43 AM
Might want to consider using the TC as is. Obviously it worked well ???  Just need to work out the control.

Just a thought(;-) TP
Title: Re: 8 position lathe toolchanger
Post by: BIGWING on June 01, 2011, 11:31:01 AM
Hi TP

Was looking to change to stepper motor as I don't think I have the electrical ability to work out dc motor drive control.

Stepper approach seems more achievable (for me)

However if anyone out the has already integrated an Emcoturn 120 turret I would love to hear from them.

I'm all in favour of saving some money

Cheers George
Title: Re: 8 position lathe toolchanger
Post by: BR549 on June 01, 2011, 12:49:47 PM
Check with TANTAN here:  http://www.machsupport.com/forum/index.php/topic,5718.10.html

Looks like he has converted one with Tool changer.

Just a thought(;-) TP
Title: Re: 8 position lathe toolchanger
Post by: PenguinAir on January 25, 2017, 04:21:30 PM
HI Bigwing

I also have a turn 120.  I would like to know how much voltage is used for the sensors and on what pins it uses.
Thanks
Penguinair ;)
Title: Re: 8 position lathe toolchanger
Post by: Graham Waterworth on January 26, 2017, 07:20:06 AM
There is a M6Start.m1s on here somewhere to run that tool changer using the DC motor I know this because I did the code for it.

Title: Re: 8 position lathe toolchanger
Post by: BIGWING on January 26, 2017, 12:37:37 PM
Hi Penguinair

I am not the best person to ask as my Electrical knowledge is very limited.

I read the diagram (may be wrong but see sensor outputs attachment above) as 24v supply but I was not able to

correctly decipher the pin outs and managed to smoke my board. !!**@@**!! The price for a replacement from

Emco was circa £300 GBP  So I managed to replicate the boards function using off the shelf parts for about £5 GBP

(see attachments) Basically it is just 4 photo interrupter sensors used to produce the output signals. The schmitt

trigger inverter conditions the output to be either 0 or 1 nothing in between. Note the attached diagram only shows

the circuit for one sensor obviously the complete circuit requires four. The outputs were sent via a pokeys  to a tool turret brain.

(see working solution @ machsupport forum/mach discussion/brains development /" compare immediate not working" BIGWING

www.machsupport.com/forum/index.php/topic,30316.0.html

This program followed the truth table to give a value for the current tool which I used in my modified M6Start.mls program

to index the turret.

However I am aware that there is a ready made control solution to the emco tool turret with a complete integrated package

in mach. I think the developers name is Andy Barrow. I think the company name is barrow dynamics but I might have my wires crossed there.

Best idea is to google it. I am sure if you get in touch with him he will know what the correct pin outs are for the Emco board

and save you a lot of work.

Cheers George
Title: Re: 8 position lathe toolchanger
Post by: PenguinAir on January 26, 2017, 01:03:47 PM
BIGWING
THANKS FOR THE HELP.
RICHARD
Title: Re: 8 position lathe toolchanger
Post by: BIGWING on January 29, 2017, 09:09:02 AM
Richard

Just realised I missed off the resistor values in my circuit diagram. From my research the 270 Ohms resistor is a current limiting resistor and if you leave it out

you will fry the sensor (suggested range 180 Ohm to 2.1 kohm) . The 270 kohm resistor is a pull up resistor with suggest range (2 kohm to 470 kohm)

This is the extract from the site where I got the info (let's make robots)

 "Finding the exact values needed to make the photo interrupter work is a bit tricky.

Play with different values of both resistors to get a good response. The idea is to have high enough voltage when the slot is blocked to register as a HI input but also

be close to ground when the slot is blocked. If it doesn't get to ground then either the current - limiting resistor is too strong or the pull up resistor is too weak.

If the signal line doesn't get high enough, you may need to lower the resistance on the pull up resistor."


The values I chose seem to work well for me. Hope this helps.

Also I don't think my explanation of the system logic was clear.

When configuring pokeys to accept these 4 sensors they should be assigned as INPUTS 1 to 4  (not outputs)

I have tweaked the turret position diagram and added truth table for clarity.

I have also added the brain for completeness.

Please note that bugs contained within the brain software impose certain restrictions on it's use

One of these I found was that the program would only work if it was short enough to fill one page only.

So to shorten the number of lines of the program some of the superfluous statements were removed.

ie tool position 2 is uniquely described by the conditions Input 3 And Input 4  are zero's.

No other tool position has that condition

program lines containing Input 1 and Input 2 can be removed.

Cheers George   
Title: Re: 8 position lathe toolchanger
Post by: PenguinAir on January 30, 2017, 10:20:37 AM
Thanks Bigwing