TimothyMoulder
Member
So I've decided to at least sip the IEC 61131-3 Kool-Aid and dig into it a bit. It seems like a useful language, at least in the sense that so many people are using it now. And I reeeeeeeally want to use UDFBs. Badly.
I'm tooling around with Panasonic (sic Aromat sic Nais) FP-Sigma PLC, and fiddling with some code in FPWIN Pro. I haven't obtained the PLC to actually download and play around, so while I've gotten the thing to compile, I'm still thrashing around in the shallow end of the pool.
So I wanted to throw out a few basic beginner's questions to see if anybody might be able to explain. Somehow, all my reps are out of town the rest of the month...
1. How is this thing scanned? I'm used to motion control, which is line-by-line execution (with each line waiting to complete before the next is executed), and ladder, which is continuous scan. Since this software encompasses so many languages, is the scan line-by-line, continuous, or does it depend on which of the 5 protocols you are using? If I call an ST function block from my ladder, does the entire program freeze until the FB completes?
2. If I have a ladder net, and in that net is an FB using various IO variable, does the FB have to be connected to the power rail in some manner to be scanned? If not, will it simply be ignored and passed over, or will it set all it's internals to "0"?
I apologize for being so basic, but I couldn't find anything specific with searches regarding the ladder scan.
Thanks,
TM
I'm tooling around with Panasonic (sic Aromat sic Nais) FP-Sigma PLC, and fiddling with some code in FPWIN Pro. I haven't obtained the PLC to actually download and play around, so while I've gotten the thing to compile, I'm still thrashing around in the shallow end of the pool.
So I wanted to throw out a few basic beginner's questions to see if anybody might be able to explain. Somehow, all my reps are out of town the rest of the month...
1. How is this thing scanned? I'm used to motion control, which is line-by-line execution (with each line waiting to complete before the next is executed), and ladder, which is continuous scan. Since this software encompasses so many languages, is the scan line-by-line, continuous, or does it depend on which of the 5 protocols you are using? If I call an ST function block from my ladder, does the entire program freeze until the FB completes?
2. If I have a ladder net, and in that net is an FB using various IO variable, does the FB have to be connected to the power rail in some manner to be scanned? If not, will it simply be ignored and passed over, or will it set all it's internals to "0"?
I apologize for being so basic, but I couldn't find anything specific with searches regarding the ladder scan.
Thanks,
TM