Topic: Data overflowing CNC buffer?

By: Greg

Posted on: Jun 18 2004 at 04:39:44 PM

Installed DNC Xp and can tranfer smaller files into the CNCs memory but when trying to drip feed larger CNC progs the machine starts cutting but then errors out almost straight away. The manual says something about data tranfer did not stop after 10 characters. (CNC is a Fanuc OM)

By: admin

Posted on: Jun 18 2004 at 06:06:58 PM

Go to easyDncXP`s setup and check that the flow control is set to Software-Xon/Xoff.

If you used easyDncXP`s autodetect feature to set it up then it`s possible that the CNC used hardware flow control during that procedure so that`s what easyDncXP detected but for Drip Feeding the OM will probably require Software FlowControl (XonXoff) so you`ll have to change that manually in easyDncXP`s setup screen. :idea:

Thanks for using easyDnc

By: gm3211

Posted on: Aug 9 2004 at 10:39:16 PM

Also - you might want to check the FIFO under the comm port setting. Depending on the Windows operating system, the FIFO buffers might be missing with the communication. Use NONE or uncheck.

Also, try setting the data settings in DNCXP as something like a line delay or chacacter delay if it has it.

Greg

By: bw14624

Posted on: Aug 19 2004 at 10:57:23 PM

I had the same problem, seemed the controller was not sending an ok to the computer to send more data. I set the block delay, from fast, to 5, and turned off the force CR/Lf option, and it runs like a champ. I`m not really sure what the block delay does, but changing the setting worked for me on a Kuraki KV-1000 with a Fanuc 11M controller. I guess you might just have to mess around with the settings until you find something it likes. :)

By: admin

Posted on: Aug 20 2004 at 10:16:45 AM

Hello bw14624. Thanks for your suggestion. yes, sometimes just a little trial and error might be required and any suggestions from users via this forum is most certainly appreciated.

Explantation of the Block Delay.
In the case of the fanuc11 - What happens is that the computer sends data until it`s told to stop. Kind of the oposite of an OK if you see what i mean. When talking to your Fanuc 11 the computer assumes it`s always OK to send the next block unless told otherwise by a Stop command.

The block delay makes easyDncXP pause just a little while between blocks mainly to give the CNC time to clear its buffers before the next block arrives but also to give the CNC time to realise it`s buffers are full and to send a Stop command preventing an overflow.

The number relating to the block delay is simply the length of the pause in characters spaces. IE if you select 5 then it pauses the length of time it would normally take to send 5 characters or the same as 5 tractor holes on ISO punch tape because in this case easyDncXP is making your computer behave like a standard fanuc paper tape device (At 1200baud a 5 character delay is around 5/100ths of a second so not very long (But in bw`s case it`s long enough) so don`t be afraid to use the block delay.

Topic: Data overflowing CNC buffer?

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