Introduction

Each action that is linked to a step must have a qualifier which defines the control for that action.

NOTE: The execution behavior of an action section is dependent whether the option SFC action behavior: Final Scan logic activated is activated.

N / None Qualifiers

Meaning: None stored

Description: If the step is active, then action is 1 and if the step is inactive the action is 0.

With final scan:

If the step is active, then action is 1 (ActionName.q = 1) and when the step becomes inactive the action is executed one more time with ActionName.q = 0.

R Qualifier

Meaning: overriding Reset

Description: The action, which is set in another step with the qualifier S, is reset. The activation of any action can also be prevented.

NOTE: Qualifiers are automatically declared as unbuffered. This means that the value is reset to 0 after stop and cold restart, for example, when voltage is on/off. Should a buffered output be required, please use the RS or SR function block from the standard block library.

S Qualifier

Meaning: Set (saved)

Description: The set action remains active, even when the associated step becomes inactive. The action only becomes inactive, when it is reset in another step of the current SFC section, using the qualifier R.

NOTE:

  • If an action variable is modified outside of the current SFC section, it may no longer reflect the action's activation state.

  • A maximum of 100 actions are permitted using the S qualifier per SFC Section.

With final scan:

If the step is active, then action remains active (ActionName.q = 1) and when the action is reset in another step the action is executed one more time with ActionName.q = 0.

L Qualifier

Meaning: time Limited

Description: If the step is active, the action is also active. After the process of the time duration, defined manually for the action, the action returns to 0, even if the step is still active. The action also becomes 0 if the step is inactive.

NOTE: For this qualifier, an additional duration of data type TIME must be defined.

With final scan:

If the step is active, then action is also active (ActionName.q = 1). After the process of the time duration the action is executed one more time with ActionName.q = 0. Then the action becomes 0 even if the step is still active.

D Qualifier

Meaning: Delayed

Description: If the step is active, the internal timer is started and the action becomes 1 after the process of the time duration, which was defined manually for the action. If the step becomes inactive after that, the action becomes inactive as well. If the step becomes inactive before the internal time has elapsed, then the action does not become active.

NOTE: For this qualifier, an additional duration of data type TIME must be defined.

With final scan:

If the step is active and after the process of the time duration the action becomes active (ActionName.q = 1) and when the step becomes inactive the action is executed one more time with ActionName.q = 0.

P Qualifier

Meaning: Pulse

Description: If the step becomes active, the action becomes 1 and this remains for one program cycle, independent of whether the step remains active.

With final scan:

If the step becomes active, the action becomes 1 and this remains for two program cycles. The first one with ActionName.q = 1 and the second one with ActionName.q = 0. This is independent of whether the step remains active.

DS Qualifier

Meaning: Delayed and Set

Description: If the step becomes active, the internal timer is started and the action becomes active after the process of the manually defined time duration. The action first becomes inactive again when qualifier R is used for a reset in another step. If the step becomes inactive before the internal time has elapsed, then the action does not become active.

NOTE: For this qualifier, an additional duration of data type TIME must be defined.

With final scan:

If the step is active and after the process of the time duration the action becomes active (ActionName.q = 1) and when the action is reset in another step, the action is executed one more time with ActionName.q = 0.

P1 Qualifier

Meaning: Pulse (rising edge)

Description: If the step becomes active (0->1-edge), the action becomes 1 and this remains for one program cycle, independent of whether the step remains active.

NOTE: Independent of their position in the action list field, actions with the qualifier P1 are always processed first.

With final scan:

If the step becomes active (0->1-edge), the action becomes 1 with ActionName.q = 0 and this remains for only one program cycle, independent of whether the step remains active.

P0 Qualifier

Meaning: Pulse (falling edge)

Description: If the step becomes inactive (1->0-edge), the action becomes 1 and this remains for one program cycle.

With final scan:

If the step becomes inactive (1->0-edge), the action becomes 1 with ActionName.q = 0 and this remains for only one program cycle.