Single-Trigger Sequencer
medium
Advances through three steps using one shared Next button.
What it teaches
Your first explicit state sequencer: one state number, three mutually exclusive active-step flags, and one shared edge-triggered input that advances every step. The manual-advance skeleton — an operator stepping a machine through setup positions one press at a time.
Parameters
| Tag | Direction | Type | Default | Description |
|---|---|---|---|---|
| In_Next | Input | BOOL | 0 | Each press advances to the next step |
| In_Reset | Input | BOOL | 0 | Returns the sequencer to Idle |
| Sts_Step1Active | Output | BOOL | 0 | 1 only while step 1 is active |
| Sts_Step2Active | Output | BOOL | 0 | 1 only while step 2 is active |
| Sts_Step3Active | Output | BOOL | 0 | 1 only while step 3 is active |
| Sts_Step | Output | DINT | 0 | 0=Idle, 1=Step1, 2=Step2, 3=Step3 |
Required behavior
- A fresh block starts in Idle with Sts_Step at 0 and all active-step flags off.
- Each 0-to-1 transition of In_Next advances one position: Idle to Step1, then Step2, then Step3.
- Exactly one active-step flag is on in steps 1-3; holding In_Next does not skip steps.
- Step3 holds until In_Reset returns the sequencer to Idle.
- In_Reset wins if it is on in the same scan as a new In_Next press. That press is discarded; releasing Reset while Next remains high does not advance.