def identify_max_range_columns(data_frame, described_df, num_columns=50):
    """
    Returns a list of columns with the maximum absolute ranges.
    :param data_frame: pandas data frame
    :param described_df: pandas data frame with summary statistics
    :param num_columns: number of output channels to return
    :return: list of output channels with maximum ranges.
    """
    data_frame.columns = data_frame.columns.map(str)
    described_df['range'] = described_df['max'] - described_df['min']
    described_df = described_df.sort_values(by=['range'], ascending=False)
    output_channels_needed = described_df[:num_columns].index

    output_channels_needed = [str(i) for i in output_channels_needed]
    return output_channels_needed