Examples

Runnable scripts live in the repository examples/ directory.

Traffic Light Simulator

Source: examples/traffic_light.py

What it demonstrates:

• ClickServer + MemoryDataProvider simulation loop
• State transitions (RED -> GREEN -> YELLOW) via bulk_set
• Generating CLICK files:
• traffic_light_nicknames.csv
• traffic_light_dataview.cdv

Run:

uv run python examples/traffic_light.py

Sync PLC Date/Time

Source: examples/sync_clickplc_datetime.py

What it demonstrates:

• Multi-PLC concurrent updates with asyncio.gather
• System register writes for date/time:
• Date: SD29, SD31, SD32
• Time: SD34, SD35, SD36
• SC trigger/error handshake:
• Date apply: SC53 trigger, SC54 error
• Time apply: SC55 trigger, SC56 error

Run:

uv run python examples/sync_clickplc_datetime.py

Set targets and datetime directly in the script footer:

dt_now = datetime.now()
plc_ip_addresses = [
    # "192.168.1.10",
    # Add more IP addresses as needed.
]

Going further: ladder logic with pyrung

The traffic light above uses asyncio.sleep for timing — Python drives the state machine. A real CLICK PLC runs timer instructions in ladder logic. pyrung lets you write that logic in Python and simulate it scan-by-scan:

from pyrung import Bool, Char, Int, Rung, on_delay, copy, program, Tms

State = Char("State")
GreenDone, GreenAcc = Bool("GreenDone"), Int("GreenAcc")

@program
def logic():
    with Rung(State == "g"):
        on_delay(GreenDone, GreenAcc, preset=3000, unit=Tms)
    with Rung(GreenDone):
        copy("y", State)
    # ... yellow → red → green

Under the hood, pyrung provides its own DataProvider that bridges ladder state to ClickServer — so any ClickClient or Modbus tool sees live, scan-driven values instead of Python-controlled ones.

See pyrung's traffic light example for the full version with timers, car counters, and deterministic scan stepping.