Program editor / LAD
STOP20 ms scanTank Level Control
Project explorer
Local PLCBrowser simulation · BOOL
Program blocks 8
Local simulationNo controller connected
Task / brief
Goal
Pump runs while filling, stays on between thresholds (hysteresis), and switches off at LevelHigh. Restarts at LevelLow.
Inputs / outputs
Level low sensor: 1 (automatic)
Level high sensor: 0 (automatic)
Hints
Main [LAD]Modified
Network 1
Properties coil · 2 paths
Contacts & branches
Path 1
1
2
Path 2
1
2
Output instruction
Q 0
1 networks · 3 tagsSelect a symbol to edit its properties
PLC tags / I/O table (3/64)
%I Input · %Q Output · %M Internal bit / byte.bit (0–7)
Address naming rules
| Area | Meaning | Example |
|---|---|---|
%I | Input | %I0.0, %I0.1 |
%Q | Output | %Q0.0, %Q1.0 |
%M | Internal bit | %M0.0, %M0.1 |
- Format: %areaByte.bit. Bytes: 0–65535; bits: 0–7. After %I0.7 comes %I1.0, not %I0.8.
- Enter I1.2 or i1.2 to normalize to %I1.2. Addresses must match the direction and be unique.
- Symbol names appear above ladder elements; addresses appear below. All contacts bound to a variable share its address.
- These BOOL addresses are for simulation. The byte limit does not describe every physical CPU.
| Symbol | Address | Direction | Type | Initial | Live | Comment | |
|---|---|---|---|---|---|---|---|
| LevelLow | BOOL | ||||||
| LevelHigh | BOOL | ||||||
| Pump | BOOL |
Addresses are saved with the project. Existing tags keep their addresses when another tag is deleted. Exercise IDs keep their physical role.
Simulation / live I/O
Device feedback
StoppedPUMP
Variable table
3| Name | Address | Value | Control |
|---|---|---|---|
| Level low | %I0.0 | 1 | |
| Level high | %I0.1 | 0 | |
| Pump | %Q0.0 | 0 |
Addresses are virtual teaching tags.
Diagnostics / verification5 cases
Test 1 of 5
Entire suite · isolated engines · results clear on edit
Test 1: Low level starts the pump
Click Run test to evaluate the entire suite.