Correct counting results depend to a large extent on the appropriate choice of pulse generator. In mechanical pulse generators, bounce contact of > 3 ms should not occur, as miscounts will otherwise be registered. For counting rates of up to 10 Hz, microswitches, limit switches, limit switches or cam-actuated sets of contact springs are suitable; for counting rates of up to 30 Hz, miniature relays can be used. The use of electronic pulse generators (proximity switches, light barriers, shaft encoders, etc.) is recommended for counting rates higher than 30 Hz.