Please Help, How To Connect PC's Com Port To 1747-KE

I am working on a school project and is using a PLC(SLC500) with SLC 5/01 processor.
The PLC is connected to a conveyor system.
I need to monitor and control a ladder program that has been downloaded into the PLC.
By doing this, I need to read or write bits directly to the PLC.
The PLC has 1747-KE module installed. This module enhances the PLC with DF1 protocol.

I need to connect my PC's COM port to the DF1 port of the 1747-KE in order to monnnnitor the PLC.

To do this,
Do I need to use modems or just a regular Female-Female 9-pin serial cable to connect them directly?

I am writing a visual basic program that will read/write to PLC via DF1 protocol.

Please help,
Thank you,
Tom

While the 1747-KE module allows you to attach modems to the RS-232 DF1 port, it's not required. A regular old "null modem" RS-232 cable such as the Allen-Bradley 1747-CP3 will do fine. If you're building your own, generally all you need to connect are pins 2, 3, and 5, being sure to swap the connections between 2 and 3 to connect Tx to Rx and vice-versa.

Is part of the project the writing of the DF1 driver ? If not, you sure can do things easier with DDE and OPC access through RSLinx or one of the 3rd party ActiveX DF1 drivers. There have been dozens of threads about those on this forum.

If the driver is the whole point of the project, you definitely need to get the book Home Automation Basics by Thomas Leonik. Search through the archives here for other web and written resources.

Questions !!

Hi Ken,

Thank you very much for your useful information.
Writing DF1 protocol is not a requirement. I only need to be able to set and write bits directly to the PLC.

Basically, I am looking for an easy way to do so.

You mentioned that DDE or OPC would help. However, I really have no idea about them. Are they some kind of DF1 drivers that are used through RSLinx? If not please correct me.

Do DDE or OPC provide any Visual Basic functions that let me read or write bits to the PLC?

My version of RSLinx is RSLinx Lite which came with RSLogix Standard edition. In order to use DDE or OPC, do I need any additional software?

If I really need to develop my own DF1 driver, is it possible to access to the PLC's memory through the DF1 port of the 1747-KE module?

Thank you very much,
Tom