How to See the Following of Data from PC to Servo Drive

Signode,

The resolution on your diagram is too low for me to read any of the labels on the lines going to the motors. I will assume that they are RS-485 lines. In that case, your best spy port will be through an RS-485 to USB or an RS-485 to RS-232 converter. Plug the converter into another pc with a terminal program such as Realterm. Then hook the RS-485 side into one of the motor connections.This will let you view exactly what messages are being sent and received when your DOS pc communicates with the motors.

Dave

Probably the simple way would be to insert a breakout box and a wye on the DB9 connector and monitor the communications lines on a second computer (using something like minicomm or terminal, if you insist on using Windows). In the old DOS days, they had a tendency to use the control lines as well as the signal lines, which is why you should have the breakout box. The wye lets you monitor the traffic. Decoding the traffic might be a problem (ASCII code? 8 or 16 bit binary?).

RS485 does not specify pin out- however, you might have sufficient information here to convert the entire operation to a more modern setup (say, through an Ethernet or usb to RS485 connector).

What is the language used on the old DOS machine? How are the parameters specified for the DOS-based program? I am pretty sure that you are working with an old, old system- maybe the original equipment manufacturer would be willing to give you access to the source code?

It is late on Sunday evening, so going in to more detail is a bit difficult with this glass of red wine sitting next to the computer. Send me a PM and we can explore this further- like, what is your ultimate goal?

Break out at rs232 then to your pc's serial port.

Run Hyperterminal. Alter the emulation type, handshaking protocol and speed until you can read something useful.

That will give you the data in ASCII.

What type of parameter that is will depend on the coding and packet spec for which you will need the documentation or somebody (who is still alive and still cares) who just knows it....

Dear Friends;

Thanks for participation.

As i told that the system is very old, we want to replace the old electronics with PLC and this is the study of current system.

We can't disconnect the RS232 connector from PC to see what type of data is following as when we open, system go in fault. The PC is a BLACK BOX and we dont know what type of program is inside it. There is no help from OEM. Once we tried to brought out two wires, one from ground and other from Txs and connect this wires with DB9 connector and then with an Hyperterminal of Laptop but doing so, signal strength got weak and system put in fault.

You misunderstand what was said, you "T-Off" each signal only, you don't "break" any of them.

Some companies actually manufacturer "break-out" boxes that do this easily, they just cost money.....

As the data will usually be quite fast, you need to set up Hyperterminal to save to a file as ASCII.

Understanding what it actually does is another thing though.....

.......Make it simple & easy.....go or look at PARKER HANNIFIN servo drive division and ask them (or look your self through the web) for the origininal software to program the Parker Drives you are using to move your servomotors.

Oance you have the original software, will be very easy to find all sorts of info like that you are looking for.

Now,...you will have to get the DOS software and the WINDOWS vertion that works with it(probably WINDOWS 95) in order to be able to make programs and communicate with the drives. It will be easy to find the DOS & WINDOWS vertion you need on the web for free or for a cheap cost.

If this is a cost sensitive issue, use one of those old lap-tops with 1 1/2→ 5 GB HDD

with rs232/rs485 DB9 ports to be able to establish communications with the converter.

This way every thing will be fun and easy.

Hope this will help.

Old laptop!!!

Some new ones still have serial data ports mate.

You are right about using a PC that has these (deemed to be obsolete by some in the IT fraternity) ports as part of their build to keep things fun and easy.

RS232USB dongles were problematic things as I recall. Apparently they are better now. I don't need them with my laptop and I like it that way..

I think yr old PC has a DNC software based on MS DOS.

Nowadays we have the softwares based on Windows and other operation system.

Normally, we do the programming in softwares like Mastercam etc. and then create a NC file through the same software.

This file is now transmitted to the machine vis RS-232 connection.

In my opinion, you can try to create a NC file for some cutting operations in window based operating system and then transmit to yr machine through RS 232 using a window based DNC software..