LiDAR scan range setting

[seongminJadenLeeunib]

I am doing SLAM using a2m8.

I have a question.
What I want to do is as follows.

1. Scan only -90 to 90 degrees
2. Read data only 30 centimeters or more from the lidar origin

How do I set these two settings?

`
#!/usr/bin/env python3

import os

from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.actions import LogInfo
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node

def generate_launch_description():
channel_type = LaunchConfiguration('channel_type', default='serial')
serial_port = LaunchConfiguration('serial_port', default='/dev/ttyUSB0')
serial_baudrate = LaunchConfiguration('serial_baudrate', default='115200')
frame_id = LaunchConfiguration('frame_id', default='laser')
inverted = LaunchConfiguration('inverted', default='false')
angle_min = LaunchConfiguration('angle_min', default='-1.5708')
angle_max = LaunchConfiguration('angle_max', default='1.5708')
range_min = LaunchConfiguration('range_min', default='0.1')
angle_compensate = LaunchConfiguration('angle_compensate', default='true')
scan_mode = LaunchConfiguration('scan_mode', default='Sensitivity')

rviz_config_dir = os.path.join(
        get_package_share_directory('sllidar_ros2'),
        'rviz',
        'sllidar_ros2.rviz')

return LaunchDescription([
    DeclareLaunchArgument(
        'channel_type',
        default_value=channel_type,
        description='Specifying channel type of lidar'),

    DeclareLaunchArgument(
        'serial_port',
        default_value=serial_port,
        description='Specifying usb port to connected lidar'),

    DeclareLaunchArgument(
        'serial_baudrate',
        default_value=serial_baudrate,
        description='Specifying usb port baudrate to connected lidar'),
    
    DeclareLaunchArgument(
        'frame_id',
        default_value=frame_id,
        description='Specifying frame_id of lidar'),

    DeclareLaunchArgument(
        'inverted',
        default_value=inverted,
        description='Specifying whether or not to invert scan data'),

    DeclareLaunchArgument(
        'angle_compensate',
        default_value=angle_compensate,
        description='Specifying whether or not to enable angle_compensate of scan data'),

    DeclareLaunchArgument(
        'scan_mode',
        default_value=scan_mode,
        description='Specifying scan mode of lidar'),

    Node(
        package='sllidar_ros2',
        executable='sllidar_node',
        name='sllidar_node',
        parameters=[{
            'channel_type': channel_type,
            'serial_port': serial_port, 
            'serial_baudrate': serial_baudrate, 
            'frame_id': frame_id,
            'inverted': inverted == 'true',  # Convert string to bool
            'angle_min': angle_min,  # Keep as string for now (unless the node expects float)
            'angle_max': angle_max,  # Keep as string for now
            'range_min': range_min,  # Keep as string for now
            'angle_compensate': angle_compensate == 'true',  # Convert string to bool
            'scan_mode': scan_mode,
        }],
        output='screen'),
])

`