Hi,
I understand that all physical inputs are scanned during the "input scan" before the "program scan" phase.
But is this true for internal relay, contacts & registers also?
i.e.(1) Are internal relays energised during "Output scan phase" or do they get energised immediately as the rung logic goes true?
2) The state of contacts corresponding to internal relays: Is it checked only at the beginning of the program or is it checked each time the element is encountered?
The "How a ladder is scanned" topic in your contents seems to suggest that internal contacts are checked each time they are encountered in a rung. Your help will be highly appreciated.
regards
Viswesh
I understand that all physical inputs are scanned during the "input scan" before the "program scan" phase.
But is this true for internal relay, contacts & registers also?
i.e.(1) Are internal relays energised during "Output scan phase" or do they get energised immediately as the rung logic goes true?
2) The state of contacts corresponding to internal relays: Is it checked only at the beginning of the program or is it checked each time the element is encountered?
The "How a ladder is scanned" topic in your contents seems to suggest that internal contacts are checked each time they are encountered in a rung. Your help will be highly appreciated.
regards
Viswesh