PLC_cascade_ouputs

#!/usr/bin/env python3
import socket
import time

PLC_PORT = 2101

def bcc_xor(data: bytes) -> bytes:
    """XOR BCC, returned as 2 ASCII hex chars."""
    b = 0
    for x in data:
        b ^= x
    return f"{b:02X}".encode("ascii")

def frame(msg: bytes) -> bytes:
    """Append BCC + CR."""
    return msg + bcc_xor(msg) + b"\r"

def recv_until_cr(sock: socket.socket, limit: int = 4096) -> bytes:
    """Read until CR or socket timeout/close."""
    buf = bytearray()
    while len(buf) < limit:
        chunk = sock.recv(256)
        if not chunk:
            break
        buf += chunk
        if b"\r" in chunk:
            break
    return bytes(buf)

def xmit(ip: str, payload: bytes, timeout: float = 2.0) -> bytes:
    with socket.create_connection((ip, PLC_PORT), timeout=timeout) as s:
        s.settimeout(timeout)
        s.sendall(payload)
        return recv_until_cr(s)

def write_y_bit(ip: str, bit_index: int, value: int, device: str = "FF") -> bytes:
    """
    Write 1-bit output using request message 1:
      ENQ + Device(2 ASCII) + '0' + 'W' + 'y' + addr(4 ASCII) + ('0'/'1') + BCC + CR

    Data type 'y' = Output 1-bit designation. :contentReference[oaicite:1]{index=1}
    """
    if bit_index < 0 or bit_index > 7:
        raise ValueError("This demo expects outputs 0..7")
    if value not in (0, 1):
        raise ValueError("value must be 0 or 1")

    # Address as 4 ASCII digits (matches your existing style, e.g. 0004)
    addr = f"{bit_index:04d}".encode("ascii")

    msg = b"\x05" + device.encode("ascii") + b"0W" + b"y" + addr + (b"1" if value else b"0")
    return xmit(ip, frame(msg))

def demo(ip: str):
    # Turn outputs on one-by-one (0 -> 7)
    for i in range(8):
        rx = write_y_bit(ip, i, 1)
        print(f"TX: set Y{i}=1 -> RX: {rx!r}")
        time.sleep(1)

    # Hold on for a moment (optional)
    time.sleep(1)

    # Turn outputs off one-by-one (7 -> 0)
    for i in range(7, -1, -1):
        rx = write_y_bit(ip, i, 0)
        print(f"TX: set Y{i}=0 -> RX: {rx!r}")
        time.sleep(1)

def main():
    ip = "10.1.0.15"
    demo(ip)

if __name__ == "__main__":
    main()