Hello All,
I'm needing some help connecting a Mitsubishi Meldas 520 to a PC. I bought a null modem cable that has a DB9 connector on one end and a DB25 on the other, and I have connected the PC and CNC control together. All the parameters are properly set as per Mitsubishi's instructions-on the PC end, 7 data bits, even parity, 2 stop bits. On the controller, 8 data bits, no parity, and 2 stop bits. I'm attempting to use two different programs to transfer data. One is NCnet Lite 4.1, the other is Quick Link 2000 from Microcimm.
Whenever I attempt to download from the controller, I can see the program scrolling down the monitor, but there is nothing going on at the PC. When I try to upload to the controller, the PC sends the program, but nothing happens at the controller, other than it times out. From what I understand, I should be seeing something, even if it is gibberish. So maybe someone out there has seen something similar, and could steer me in the right direction because I'm way out of my league here. :confused: Thank You for your time. Shane.

Whoa....both serial port settings need to be the same.

On the 520, make sure you have the same port designated for send and recieve and that the device is the same, make sure the baud rate is the same, as you say, you should see something when downloading to PC, even if it is garbage, I usually use the 3 wire cable on this system, (handshake jumpered out).
Al.

Al-
Thanks for the information. You wouldn't happen to have a wiring diagram for the 3-wire cable that you could give me? Thanks for your time. Shane.

If you look up the Mitsubishi M50 it should give you the pin out for the three wire and also they have a free DNC communication s/w. http://www.cadem.com/ncnet/ncnet_dncdetails-41.htm
Al.

Hi Al-
I have soldered up a new 3-wire cable with the 1,4,6 & 7,8 jumpered together on the 9 pin, and the 8,20,6 & 4,5 jumpered together on the 20 pin. The 3-wires are going from 2-2, 3-3, and 5-7. Now the CNC controller is giving me a E04 Device not ready error. From what I can see, all the parameters are set correctly- any ideas? Thanks again for your input. Shane.

With the hardware handshake jumpered out, it should show the device as ready, so as long as there is nothing wrong with the port itself, the usual problem for this message is that the wrong port is assigned. i.e. if you are connected to 0 and 1 is assigned. Mitsubishi usually has at least two physical ports, 0 & 1
The 'devices' PC, punch etc are logical assignments and can be assigned to either port.
Al.

2 J ,
Just curious, what kind of set up,laptop or desktop,lathe, mill,edm.
Have been working on simular setup with Meldas 50 to laptop through
usb to DB25 to RS232 (wierd results so far,nothing useable).Maybe
if Caboose sees this thread he can help?,He was working on simmular setup.
Bear

Hello Bear,
I'm running a desktop PC using the rs-232 9 pin serial port to the CNC's 25 pin connector. The controller is a Meldas 520 on a Mighty/Viper VMC.
I've tried a null modem cable and had the controller outputing, but the PC wasn't receiving the data. When I tried to use a 3-wire cable I get a E04 Device not ready error. I'm going to build another cable and try that. I'm attempting to use two different DNC programs: Quick Link 2K from MicroCimm, and NCnet Lite 4.1. What kind of issues are you having, and what type of set up are you using? Shane.

P.S. Thanks for the info Al, I'll look into that.

Hello Bear,
I'm running a desktop PC using the rs-232 9 pin serial port to the CNC's 25 pin connector. The controller is a Meldas 520 on a Mighty/Viper VMC.
I've tried a null modem cable and had the controller outputing, but the PC wasn't receiving the data. When I tried to use a 3-wire cable I get a E04 Device not ready error. I'm going to build another cable and try that. I'm attempting to use two different DNC programs: Quick Link 2K from MicroCimm, and NCnet Lite 4.1. What kind of issues are you having, and what type of set up are you using? Shane.

P.S. Thanks for the info Al, I'll look into that.

Hi, Have you solved this problem? I'm having the same problem

I never got that networking problem sorted out. The owner of the company didn't want to spend the money to have someone come and fix it, and I have since moved on to another organization. I tried all sorts of different cable configurations, and settings in the controller, nothing worked. All I can think of is maybe the network card is no good... It might be easier to just add a disk drive to it. If you ever get your problem solved, please post it here and tell us what you did.

My machines have Mits M3 controls which are similar to the M520. I have a 9 pin to 25 pin serial cable with a null modem adapter on the 25 pin end. I use Windows Hyperterminal for file transfer with the following settings:

HT:
9600 baud
7 data bits
even parity
2 stop bits
hardware flow control

HT requires some fiddling with the terminal emulation to get the line feeds correct.

At the control, I have the settings shown in the pictures.

I have not been able to get HT to DNC yet, only transfer.

First I would try to set HT in XON/XOFF mode and try to send code from machine to computer first. let me know what hapens.