'Dnc problem for Mitsubishi Meldas 520AM'

Dnc problem for Mitsubishi Meldas 520AM

Tags: dnc

myyan71 from Singapore -

Hi, All:

Our CNC machine controller is Mitsubishi Meldas 520am(very old), PC operation system is Windows XP. RS232 connection: CNC Machine -- 25pin -- 25 pin -- converter -- 9pin--PC.

I have no problem to send very very small NC programs to CNC machine using ConnectCNC.( Using Xon/Xoff flow control, baud rate 4800, data bits:7, stop bits:2, parity: even). Since the memory at machine side is very small (less than 100k), I try to use DNC, but don't succeed, with error "P460 TAPE I/O ERROR". ConnectCNC does not seem to care about whether the CNC machine is ready for receiving or not, and it just sends the NC program after the SEND button is pressed. It never waits for a Xon singal.

The funning thing is that the machine can't receive a small NC program when I use " Wait for Xon" function in other software such as Cimco edit (same settings as ConnectCNC on both PC and machine sides).

so my stupid questions are:

Is the Meldas 520 using the same port for data receiving and sending?(There is only one port on machine).

Which handshake is better for this old machine( Xon/Xoff or hardware handshake or no handshake)?

Any suggestion will be appreciated.

Thanks in advance.

Comment #1 Deepak Bodhani from Pune, India -

Use our DNC Software. email me on digitech@vsnl.com. Also see more information at digitech-engineers.com

Set parameter no. 8109 as 1 on Mitsubishi.

Use Xon-X-off for hand shaking. It should work well. - Deepak

Comment #2 bj0629 from Peking -

The protocol of hardware and software are the same result.

As you know when cnc trans a xoff(hex 13) computer has to pause

transfer program immediately. But some dnc software happens over transfer and then CNC alarm. Normally cnc allows over flow 10-20 chars. In actually some cnc can not overflow 1 char especially when cnc system has too much user programs. Too much user program will influence system speed. So you can write a correct dnc software that is important or you have a correct software is important.

Another when you use dripfeed mode you have to use xon/xoff or handshake. Because when CNC receive buffer is full CNC will sent xoff or output handshake signal (RTS pin 4) to pause computer transfer. When cnc buffer has empty bytes cnc will sent xon(hex 11) or change RTS's output voltage level to notice cnc transfer continually. I'm afraid my poor english.Any question can mail.

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