sapoleon
Member
I was working with a college, and we had a nice discussion where he told me that according to his experience, it takes less working memory in the plc (S7-3/4xx) writing the control modules (small routines) like an FC and using one big DB for memory purposes.
I never used that method, I normally write the control modules like an FB where I use stat for the values that need to be retentive from cycle to cycle, and then make a nice big FB where I call the small FBs in the stat...
So, more for curiosity... which one is a better approach? and the FC approach really takes less working memory?
thanks.
btw, use less working memory was a bit of a necesity because we were using SW redundancy in with S7-315, and when activating the SW redundancy it uses double of the working memory!
I never used that method, I normally write the control modules like an FB where I use stat for the values that need to be retentive from cycle to cycle, and then make a nice big FB where I call the small FBs in the stat...
So, more for curiosity... which one is a better approach? and the FC approach really takes less working memory?
thanks.
btw, use less working memory was a bit of a necesity because we were using SW redundancy in with S7-315, and when activating the SW redundancy it uses double of the working memory!