PLC_IO+ACK/NAK

#!/bin/bash
set -euo pipefail
# Send PLC commands AND show ACK NAK
HOST="192.168.1.50"
TCP_PORT=2101
DELAY=0.15
RX_TIMEOUT=0.5
RX_MAX_BYTES=64

read_response() {
    local data

    data=$(timeout "$RX_TIMEOUT" dd bs=1 count="$RX_MAX_BYTES" <&3 2>/dev/null | xxd -p -c 256 || true)

    if [[ -z "$data" ]]; then
        echo "[RX] <timeout/no response>"
        return
    fi

    printf '[RX HEX] '
    echo "$data" | sed 's/../& /g'

    case "$data" in
        06*)
            echo "[RX] ACK"
            ;;
        15*)
            echo "[RX] NAK"
            ;;
        *)
            printf '[RX ASCII] '
            echo "$data" | xxd -r -p | sed -n 'l'
            ;;
    esac
}

send_frame() {
    local frame="$1"

    printf '[TX] '
    printf '%b' "$frame" | xxd -p -c 256 | sed 's/../& /g'

    printf '%b' "$frame" >&3

    read_response
    sleep "$DELAY"
}

echo "[*] Connecting to ${HOST}:${TCP_PORT} ..."
exec 3<>"/dev/tcp/${HOST}/${TCP_PORT}"

echo "[*] ON sequence"
send_frame '\x05FF0Wy000012A\r'
send_frame '\x05FF0Wy000112B\r'
send_frame '\x05FF0Wy0002128\r'
send_frame '\x05FF0Wy0003129\r'
send_frame '\x05FF0Wy000412E\r'
send_frame '\x05FF0Wy000512F\r'
send_frame '\x05FF0Wy000612C\r'
send_frame '\x05FF0Wy000712D\r'

sleep 5

echo "[*] OFF sequence"
send_frame '\x05FF0Wy000702C\r'
send_frame '\x05FF0Wy000602D\r'
send_frame '\x05FF0Wy000502E\r'
send_frame '\x05FF0Wy000402F\r'
send_frame '\x05FF0Wy0003028\r'
send_frame '\x05FF0Wy0002029\r'
send_frame '\x05FF0Wy000102A\r'
send_frame '\x05FF0Wy000002B\r'

exec 3>&-
echo "[*] Done"