CommonWealth Scientific Corporation, Robot chamber

[jack17]

in the above diagram,

i could trace the flow of execution for open/close valve command.
But,I'm stuck when the TCC.cpp communicates with the ARTCOMM.cpp.

Is there any specifc format, template etc i can look for where i can identify the location in code where the program communicates with the PLC.
i want to find that particular handle tat does the communication from the Program to the PLC.

Jack

 

[Steve Bailey]

The PCM301 and PCM311 modules are BASIC coprocessor modules. They are probably running their own applications and passing data between varaibles in their BASIC programs and addresses in the PLC.

However, it is also possible that the builder is using the PCM modules as communications interfaces. If that is the case, then the PC is using either SNP or CCM serial communications protocol to talk to the PLC.

If you have a listing of the BASIC source code, look for SYSLINK, SYSREAD and SYSWRITE statements in it. That's how the data is passed from the BASIC application to the PLC. The SYSLINK statement links a BASIC variable to a PLC address. SYSWRITE writes the BASIC variable's value to the PLC and SYSREAD gets a value from the PLC and sets a BASIC variable equal to it.

That's a pretty complex system you have there. Don't you have any documentation from the manufacturer? If not, why not?