I'm happy because these past 2 weeks I have been working to decode and interpret the communication between the LOGO! PLC and a PC. Well ... I finished this work and achieved the following:
-Ask the status of communication between PC – LOGO! PLC
-Ask the status of the PLC (The PLC responds RUN/STOP status)
-Forcing the status of the PLC to RUN mode.
-Forcing the status of the PLC to STOP mode.
-Ask the current values (in real-time) of all channels of the PLC:
o 24 digital inputs
o 16 digital outputs
o 8 analog inputs
o 2 analog outputs
o 24 digital marks
o 6 analog marks
o 4 cursors
The application developed in LabVIEW performs the main function of communicate the Desktop / Laptop with PLC LOGO! (That is to say link National Instruments with Siemens ... ja ja).The software performs the following functions:
-Monitors and displays all channels of the LOGO!
-Choose the communication port.
-The user can save in a file all the data, each configurable period.
I have made many tests with different logic modules, and it has not given any problems.
In the image attached, I show you some of the topologies that can be implemented knowing this protocol of communication. I ask you to spread this to engineers/technicians who design and implement these MICRO-AUTOMATION systems, in order to offer this Software applicable to supervisory system or data-logger device.