[barchdesigns]

Neither of my Fanuc 6M Vertical CNC machines had a way to truly "drip feed" through the 25 pin serial port. The serial port was only used for transferring a program from an external computer into the NC's memory, and not for drip feeding commands as it is running.

It seemed the only way to run a very large program was through the old Paper Reel to Reel Tapes. After looking into the electronics of how the tape drive worked (and determining I had a bad head reader) I decided to find a way to make a Tape Drive Emulator so that I could use this machine with very large programs. I made am interface board that has an Arduino MEGA with an attached shield with a Network Port on one end, and a Multipin Ribbon Cable Receptacle on the other end. It has been in service daily for over 2 years now without an issue. It has been put to the test and the only limitation is the size of the micro SD card. With gigabytes to play with I didn't have any space limitations anymore.

Has this been a problem for anyone else? I'm trying to determine if I should document and share the information of how I solved this problem.


Barch Designs
877-201-9771

[aarggh]

This is absolutely of no use to me, but this kind of info would be priceless to someone struggling with a similar issue, so yes, please document it and post it as I'm positive others will find it useful at some point!

Better to have it and not need it than need it and not have it I reckon.

cheers, Ian

[gfacer2]

I agree, sounds like an awesome upgrade. Just the sort of thing that makes cnczone a great place.

Sent from my LG-D852 using Tapatalk

[barchdesigns]

Let me get clearer, Is anyone actually looking to put a Behind the Tape Reader (BTR) on a Fanuc 6 control, or is it a theoretical problem that could exist? I'm thinking of having a small run of professional circuit boards made to replace my prototypes, and I'm wondering if anyone would pay money for this Interface Board solution? I have to make about 10 of them to fill the minimum PCB order. If it really isn't an actual problem I'll just leave my prototypes in the machines as-is, but...

I would love to take the project further to include features such as

* Display % finished
* Current line output
* Control mid program starts

through a web app interface (Control it with your cell phone). I can only justify taking the time to work on the project though if it will directly help someone else.

[gfacer2]

Ahh, well I'm not. I just thought a post of the arduino sketch and a quick diagram or description of the connections would be invaluable to anyone else that may stumble upon this in the future.

I would think you could add all those features in the sketch relatively easily (except the last one maybe).

Sent from my LG-D852 using Tapatalk

[ovaiswahid]

Can you please share the arduino sketch with schematic so I can use it to DNC my fanuc 6M ?

[barchdesigns]

Hi, We didn't use a protocol. We literally just turned the 9th pin high or low by a delay function. The Fanuc tape reading head just turns 8 wires high or low and the 9th wire is like a firing pin. The Fanuc reads the 8 wire states when the 9th pin is active. I believe we found around 1 millisecond on and off worked about as fast as Fanuc would read it.

The arduino sketch just reads a text file character by character and then looks up the cross reference table to see what state the 8 pins should be in for that character. The arduino sets the state of those 8 pins and then makes the 9th pin active (I believe it was active low) for the delay time (just long enough for it to be read by the fanuc transistors.) To eliminate wasted time by sending non-movement characters such as comments and line numbers we also added a preview function to strip those characters before sending anything to the fanuc.

[ppaing126]

bar, thank you for the information. Yes I saw the 8 bit likely driving lines, not aware of the 9th pin. Also, good to know you use a lookup table. I saw the characters table on the manual.
I think I can do it now with your information and the manual.

I will start doing some tests.

[memoryman]

There are several btrs on the market and have been for decades. I have been involved in two designs. The 9th signal is the sprocket signal. A friend at another company told me 20 years ago that they could read ~600 chars/sec.

[ovaiswahid]

CAN we increase the baud rate between this BTR and the 6M? i have a BTR whose baud rate is fixed....the machine halts in between very small straight lines ...while simultaneously moving x , y and z axes..

[memoryman]

BTRs have been around since the '80s. The Baudrate is between 150 and 600. Doubtful that there is much demand for yet another BTR.

[barchdesigns]

My feeling from this thread it most people think it may be useful for someone else, but I haven't seen a need for it by anyone personally (as memoryman said, yet another BTR). On my particular 6M machines the baud rates are selectable up to 1,200. I've pushed it a bit beyond that manually, but any faster and it starts skipping characters. The electronics just don't go faster than that on a 6M. I also get the small pauses when running a program with many lines of short distance. Best thing I have done with the Arduino is parse each line to remove any unneeded characters before it even gets sent to the machine (Line numbers, comments, etc). Second best thing is optimize your toolpath to use arcs instead of many small straight lines (Some CAD programs are notorious for generating arcs as many small lines)

The biggest problem that was solved for me was running a 2 Million Byte file on a machine with only 32 Thousand bytes of memory. I can run the whole program from start to finish through the Arduino BTR. Where as before I would have to break up the program into many small pieces and send it over to run each piece at a time. I have eliminated the time it took to transfer the program from a computer to the Fanuc memory each time, and I don't have to be there to keep changing to the next "chunk" every hour. I can now start my machine and walk away for 8-12 hours.

As a home shop I needed to find a cheaper solution than a expensive industrial BTR (which I know are just simple electronics and you're paying for the convenience of someone else building it for you). The Arduino and some 1/8 watt resistors are basically all it took to build the prototype.

Barch Designs
877-201-9771

[ovaiswahid]

[email protected]

[ppaing126]

could you share your work...?
I need to build something alike to drip feed to my Fanuc 6M

[barchdesigns]

I'm not familiar with Yasnac controls, but I would guess it would be a similar process if the tape drives are similar technology. Basically all I did was look at how the reading head worked at the paper tape and then mimicked it electronically with an Arduino. Once I had that the rest was easy.

[Redzilla]

I'm not familiar with Yasnac controls, but I would guess it would be a similar process if the tape drives are similar technology. Basically all I did was look at how the reading head worked at the paper tape and then mimicked it electronically with an Arduino. Once I had that the rest was easy.

awesome! Did you send your gcode to the ardunio via USB or did you have to use a USB to rs232 serial adapter and send it through a max3232 chip mini board? Also on the output did you wire striat from the ardunio to the tape reader head or did you have to use a 74hc595 shift register? And can you email me the C++ program script? [email protected] I have no experience with the C++ programing, also I'm just using a ardunio uno V3

[barchdesigns]

It's great to see this thread with some activity! I actually just recorded a 5 min video for a shop owner who called me asking for information and it would be helpful to share here too. This is how I had hooked up my Arduino to my Fanuc 6M

https://youtu.be/oVgIsURlkYs

I'm digging up my old info, but I hope this video helps anyone who wants to see a quick walk through of the electrical hookup.
Attached is my Arduino code that I still use today. These Arduino's have been going daily for 5 years without errors.

Here are some notes:

Basic Overview Operation of the BTR we built:

At startup the Arduino opens a file called cnc.txt on the SD card
It then wants to send the program to the Fanuc so it starts listening to the CTS (Clear To Send) wire
When the CTS wire says it needs more data, the Arduino will set the 8 bit character wires Low or High according to the character table lookup for that character
The Arduino then turns the Sprocket In Position wire "active" (can't remember if it's Low or High) for a short amount of time (allowing the Fanuc to read the 8 bits) and then turns the Sprocket In Position wire back off.
This loops and continues until the file is completed.



It is coded for these features that you may want to ignore or remove.
* The Arduino is always waiting for a new program to be loaded to it from a computer (so we don't have to remove the SD card every time we want a new program).....although I found this feature to be harder to use than just removing the SD card and renaming the file I want to run.

* There is a Telnet server started on the Arduino that outputs a copy of what the Arduino is sending to the machine so that I can remotely see if it's still drip feeding from anywhere on my network (cell app called Termius).

* However be aware that there is a small buffer of memory bits inside the Fanuc to buffer what the Arduino (BTR) is sending. So what you see on your remote viewer is actually a few lines ahead of where the machine physically is. Not a big deal, but something to be aware of when troubleshooting.

*At the end of the program, the Arduino reloads to the beginning of the cnc.txt file and starts waiting for the CTS signal again. This is for when you are running many parts in 1 day. The Arduino will always reload itself at the end of the file so you don't have to physically push the reset button on the Arduino.

The last update we did was to NOT send Comments to the Fanuc machine, but WILL still send it out the remote telnet sever. If the Arduino finds a comment in the code, it skips sending the comment to the machine, but still WILL send the comment out to the telnet server so I can see the comments remotely. Some of my programs have large comment headers or lots of notes.....and that was stalling the machine from running smoothly when it's processing all the comments that don't actually move the machine

[barchdesigns]

*paing* In my Arduino project I had to also use a 10th wire (works like CTS, Clear to Send) that is driven high and low from the NC side which the Arduino needs to listen to. It tells the Arduino when the NC is ready for data, and when to hold from sending data.

*mem* Thanks for sharing. wouldn't this equate to 4,800 baud then. 8 bits/wires for every character @ 600 characters per second? So I guess the tape reader has a baud rate of 4800

[ppaing126]

That's what I was wondering about know when the NC is ready for more data...
My plan was to check the schematic at home, but glad you xplained here.
Thank you!

[ppaing126]

Ok, everything is ready now. First test with the DIY interface did not work. I overlooked the ASCII chars must be converted to 7 bits + 1 parity bit for the D1-D8 so the NC can understand it.
I also readjusted the Sprocket timings and the character separation. Have done simulation from 50 pin end, full circuit test and now everything goes fine. Tape feed pin is pin#25.
Comments are also stripped out.

Will test this weekend on the real 6M controller.