SR 834 Alarm Buffer Overflow 2 When Dripfeed

[TWyatt9]

Good Afternoon I'm trying to run a rather large program using my office PC it only gets so far and kicks out this error. Anyhelp would be greatly appreciated.

Thanx in Advance
Tim Wyatt
Precision Performance

[gar]

080323-1110 EST USA

TWyatt9:

You need to operate in a handshake mode. These may be classified as hardware (RTS/CTS), or software (DC codes, XonXoff, Xmodem). Also you need FIFOs disabled at your computer.

You may not want to use a USB to RS232 serial adapeter even if it appears to work for normal transfers. Many do not even work for normal transfers.

See my web site www.beta-a2.com and you will find a phone number at the bottom of almost any page.

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[TWyatt9]

I was using an old copy of Easytalk that I've had for years. When I got a hold of them they told me that it had problems with the dripfeed. So I got another DNC program and it works great.

Tim Wyatt
Precision Performance

[gar]

080326-2105 EST USA

TWyatt9:

What is the maximum baud rate of your machine?
What baud rate are you using?
Does your machine stutter on short strokes for lack of data?
How large are your files?
What is the maximum amount of CNC memory?
Do you use line numbers?
Do you use parity?
How many stop bits?

To provide some useful hints the following are provided:

Do not use line numbers if possible, or only scatter them like maybe evry 100 lines. This reduces the data transferred. Thus, improves thruput.

Using 1 stop bit instead of 2 produces a 10% improvement in thruput.

Always use parity, or Xmodem without parity. Parity detects single bit errors and stops the program. Xmodem detects and tries to correct errors. Thus, the CNC program may not be aborted with useage of Xmodem unless the error rate is excessive. A known good communication program must be used to get effective Xmodem thruput.

A higher baud rate reduces stuttering. One of my customers previouysly operated at 9600 baud on molds. This was their maximum rate both because of the CNC limitation, and the 100 ft cable length. With our I232 Isolation System they could work at 38.4 kbaud, but this required an optional modification to the CNC. Before our I232 there was considerable stuttering and data errors that caused undesired stopage on weekends when they ran an unattended program that might run for 3 days. After the increase to 38.2 kbaud and our isolation the stuttering was eliminated and also the noise, error, problem. 38.4 kbaud was the highest optional modification they could get for their CNC. Without stuttering the machining time was somewhat shortened.

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