Truncating Headlines by characters count in Schema Plugin https://schema.press/docs/truncating-headlines/

schema-truncating-headlines.php

<?php //* do not include php tag

add_filter('schema_wp_filter_headline', 'truncating_headlines_chars_567545256');
/**
 * Schema Plugin: Truncating Headlines by characters count
 *
 * @since 1.0
 */
function truncating_headlines_chars_567545256( $headline ) {
	
	$char_count 	= 110; // number of characters
	
	$short_headline = mb_strimwidth( $headline , 0, $char_count, '');
		 
	return $short_headline;
}