3 Setup and Operation 107 The plug has to be disconnected from the counter before the cables are fastened by means of screws or screw-type terminals. Caution! It is not allowed to contact the encoder to a direct current line voltage without protective circuit for EMC. For cable lenths > 30 m a protective circuit is always necessary! When programming the input level to TTL an additional protective circuit is necessary. We recommend the installation in a metallic environment. English