DNC-Buffer overload problem

[Fish]

I have been trying to set up our machine (Niigata HN50B with a Fanuc 15MA) to accept DNC and I keeep getting error SR824 - Buffer Overload on the control. The computer has a DB 9 and the control has the usual DB25. I have re-made cables twice, following the advice of the machine tool guy's and the software guy's - to no avail. Is there another parameter that I chould change? Is the machine not dumping it's memory? Any suggestions besides a large hammer?

[HuFlungDung]

Hi Fish,

What options do you have set for the control's comm handshake?

Are you able to upload and download complete files with no problem (but not in DNC mode only)?

[Fish]

Firsly, thanks for your reply. After messing withthe machine all day, I found that it will run in DNC, but at only 300 baud. It's been a long time since I milled Aluminium at 15"/min. The part should be finished by this time next month!!

To answer your question(s), I am able to upload and download programs at 9600 baud in Edit mode - no problem. I was using a PC that only had a DB9 serial connection, but I changed to another PC that has a 25 pin serial, hoping that might be the answer. The cable is connected with the 2's and 3's crossed, the 4's and 5's crossed, 6,8 and 20 tied together, and the 7's straight through. The software is set for Software Handshake, 7, even and 2. I have checked, and double checked all settings, parameters and connections - but I must be missing something.

To enable DNC on the control, aside from the parameter changes, is it enough to just choose the "Tape" key, and press start? Or could I reconfigure to use M198PO????L? in Memory mode?

Also, on board Base 1, position CA34, there is a PMC(?) cassette attached. What the hell is it? The machine has a tape reader as well. The tape reader is attached to position CD4B on the Base O board, along with the RS232 on position CD4A. Should I disable any of these?

Surely, this thing must be able to DNC faster than 300 baud. I also have a Mazak AJV that is older than this Niigata, and it will DNC at 4800.

Again, thanks for your reply.

Adam Fishman

[HuFlungDung]

Hi Adam,

I don't have your type of controller so I cannot help you specifically. Your RS232 looks a lot different than what I use on a Shadow controller (hardware handshake), for what its worth:

DB9
2 and 3 crossed
8(PCside) to 8
5 to 5+ shield
1,4,6,7 joined

DB25
2(PC side) to 2
3 to 3
7 to 5
5 to 8
Shield to 1, one end only
4,6,8,20 joined

What I'm wondering is if the controller needs hardware handshake to do DNC, as this provides a seperate signal to halt DNC, whereas software handshake requires that your controller can read XonXoff, which I understand is just a certain character (okay, I'm guessing here ) For simple program downloads/uploads, a hardware interrupt signal is not required, which is why it would still work at 9600.

In particular, note that pin 5 of a DB25 or pin 8 of a DB9 is your CTS signal, which could be critical for DNC

[hardmill]

I'd double check your para. settings again and also your
communication setting. If you can send and receive progs.
Most likely it a settings issue. Does your control have a data
server?

[Fish]

I figured it out yesterday. The solution was the line delay setting on NCLink. After trying a few different delays, I found that by delaying 300 ms, the machine had enough time to dump it's memory, and I can transfer at 9600 baud. I'm only cutting at 40ipm, so there aren't any jerking motions. We'll see what happens when an aluminium job comes up. Thanks for the help guys.

[HuFlungDung]

Isn't that almost 1/3 of a second between lines? It might work, but it still seems that something is wrong, and the real throughput would not be 9600.

[Fish]

I think it's 0.003 of a second - same as a millimetre/metre relationship......as I said, I think. I agree though, something is probably not right, however, I don't have the time to try to figure it out. I have to get these things done and out by Friday afternoon. If you think of anything else, I would appreciate your input. Thanks again for your help.

Adam

[smabhyan]

Dear Fish,

This problem is found with many DNC Softwares running in Windows Mode. They need you to delay (as you have set) between each line Transfer.

However, your DNC will work with True Software Handshake (XON / XOFF), if you use. DOS Based Software. One Such software is 'PCIN' from Siemens.

It is available with Siemens Service Persons. To Use it as DNC you must boot your PC in True DOS Mode (Press F8 while Booting & select 'Command Prompt').

With Fanuc Controls of various types I have used it at a boudrate of 19200 without problem.

SMA

[Fish]

Thanks for the info, I'll look into it. I have had quite a few problems with Windows 98 before - it would stop sending in the middle of an operation, leaving the machine to stay in one spot, spindle and coolant on, all night. I am now running 2000 because it's NT based. It is more stable, but I guess windows still tries to do too much at once. Ever tried Linux?

Oh, hey HuFlung, you're right. It is 1/3 of a second. Coffee helps to clear the mind.

Adam

[HuFlungDung]

I'd have to agree that I don't trust Windows to send DNC as much as I trust a DOS program. I use a simple nc editor called Shadcomm, from Endpoint Software, also the maker of Millwrite engraving software. The editor is sort of a sub function of the program, I guess.

Anyway, I am using an older DOS based version of Shadcomm running in a Window in windows 98 and it works good. Apparently, the DOS based version takes control of the hardware (serial port) itself, so windows cannot shut it off by going to sleep, or whatever the hell it is that windows does.

[smabhyan]

The Windows do not allow the Data Transfer Software to access the Port Directly. This makes the design of windows based software tricky. Whereas DOS directly controls the serial port , as HuflungDung has put rightly.

Surfcam is bundling a Data Transfer (DNC) software in their Pacakge. It works well.

www.cadem.com gives NCNet DNC worth Trying.

smabhyan