I'm pretty well a 100% GE/Emerson Rx3i programmer, and zero practical experience with Siemens programming. However I have just been given a PDF printout of some Siemens code and told to implement it in Rx3i ladder logic.
FWIW the code is a basic state machine that talks to some equipment on a ProfiNet interface. However some elements of the coding style confuse me and I don't know if it's bad code, or an artifact of the underlying PLC.
I have questions about 2 different rungs, but the underlying question is the same for both cases: In a single rung, do sequential writes to the same variable overwrite each other? (In an Rx3i I would be 100% certain that the original coder was less than diligent in their work.)
Example #1 - The rung is split up by what I assume is the Siemens version of an Rx3i continuation coil/contact
Example #2 - The dual writes occur in the same rung
In both cases I am asking about Tag_55, which is mapped directly onto the outgoing ProfiNet interface to the device.
So what gives?
FWIW the code is a basic state machine that talks to some equipment on a ProfiNet interface. However some elements of the coding style confuse me and I don't know if it's bad code, or an artifact of the underlying PLC.
I have questions about 2 different rungs, but the underlying question is the same for both cases: In a single rung, do sequential writes to the same variable overwrite each other? (In an Rx3i I would be 100% certain that the original coder was less than diligent in their work.)
Example #1 - The rung is split up by what I assume is the Siemens version of an Rx3i continuation coil/contact
Example #2 - The dual writes occur in the same rung
In both cases I am asking about Tag_55, which is mapped directly onto the outgoing ProfiNet interface to the device.
So what gives?
