Monitoring I/O data from a PLC Using Visual Basic


Thread Starter


I use omron CP1E NA type, my CX-programmer version 9.2, using the omron cable rs232c. and i want to monitor input and output from PLC using visual basic 6.0. i want to collect input data from PC sent to PLC and output data from PLC sent to PC. can you help me with it?

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I briefly reviewed the CX-programmer version 9.2 description and it mentions that the tool is for configuration purposes. Maybe a more in-depth look at the manual will reveal that it is possible to achieve your goal. If you want to approach this task via a different path you might want to try using OPC. MatrikonOPC has several free tools and trials you can look at to historize and read write to PLC.

Good luck..

James Ingraham

First question: Can you write a program to get data from a serial port using VB6? That's step one. If you can do that, then you can start looking at what the protocol looks like to get data out of the CP1E. I believe that reading from the serial port using VB6 has been discussed on the forum in the past, but that's a general problem that will have lots of examples you can find.

As for the CP1E itself, the User Manual Chapter 12 (at least in the 2009 version I found) covers Serial Communication. 12-6 describes what they call Host Link protocol. It also calls out a manual with more information, Communication Instructions Reference Manual (Catalog number W342). It's 267 pages long. However, I think most of that is reference material, and the information for actually writing the program is not too bad. Section 2-2 (again, a 2009 dated version) lists the request / response format, and even has sample code. The sample code is, unfortunately, in BASIC, as in old school BASIC, not Visual Basic, so it won't be very helpful.

User manual:

Communications manual CS_CJ_CP+HostLink FINS ReferenceManual.pdf

Good Luck,
James Ingraham
Sage Automation, Inc.