BL20 electronic module, Counter, Fieldbus and connection technology independent, Protection class IP20, LEDs indicate status and diagnostic, Electronics galvanically separated from the field level via optocouplers, Detection of standard counting signals, 1 digital input, 24 VDC, 1 digital output, 24 VDC, 2A, Counting mode: Continuous, single or periodic count, Measuring mode: Frequency, rotational speed or period duration measurement