I am making some changes to a PLC5 / 80 E, but is running out of memory, and I need to clean up the code in order to get some new logic to fit.
There is one unused file, B11, which contains 100 elements.
Prior to removing the file, the used space consisted of:
Program File Words: 50991
Overhead: 6768 words
Data File Words: 45236
I deleted the B11 file expecting to free up 100 words, however I ended up freeing up much more space (1062 words).
After I deleted the B11 file, the used space was:
Program File Words: 50029
Overhead: 6768 words
Data File Words: 45136
The Data File memory freed up 100 words, which makes sense. I can only assume that the remaining 962 words (50991 - 50029) came from memory necessary to allocate the data file.
I tried creating the file again, but this time with 1 element. This time it only used 1 word. I kept incrementing the file size, and as I increased the size of B11, the Program File memory would increase a little (until I hit 50991 at 100 elements).
How does the PLC5 allocate space for the B11 file? This would be different for each file type, I would think.
I would try and find a Tech Note on this, but I don't have my authorization number on-hand from Rockwell.
There is one unused file, B11, which contains 100 elements.
Prior to removing the file, the used space consisted of:
Program File Words: 50991
Overhead: 6768 words
Data File Words: 45236
I deleted the B11 file expecting to free up 100 words, however I ended up freeing up much more space (1062 words).
After I deleted the B11 file, the used space was:
Program File Words: 50029
Overhead: 6768 words
Data File Words: 45136
The Data File memory freed up 100 words, which makes sense. I can only assume that the remaining 962 words (50991 - 50029) came from memory necessary to allocate the data file.
I tried creating the file again, but this time with 1 element. This time it only used 1 word. I kept incrementing the file size, and as I increased the size of B11, the Program File memory would increase a little (until I hit 50991 at 100 elements).
How does the PLC5 allocate space for the B11 file? This would be different for each file type, I would think.
I would try and find a Tech Note on this, but I don't have my authorization number on-hand from Rockwell.
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