Specifications:
Inputs:
Input 1: frequency, rotational speed, counter input A
   Input voltage: 0 ... 5 V (0 ... 28 V with dropping resistor)
   Input level: Low < 0.5 V; High > 2.2 V
   NPN: pullup resistor 7 kohms to 3.3 V
   PNP: pulldown resistor 7 kohms against GND
   Min. pulse width: 50 us
Input 2: count input B, Gate, direction
   Input voltage: 0 ... 5 V (0 ... 28 V with dropping resistor)
   Input level: Low < 0.5 V; High > 2.2 V
   NPN: pullup resistor 7 kohms to 3.3 V
   PNP: pulldown resistor 7 kohms against GND
   Min. pulse width: 50 us
Input 3: reset input
   Input level: Low < 1 V; High > 8 V
   Min. pulse width: 50 ms
Measuring / counting areas:
   Frequency: 0 ... 10 kHz
   Speed: max. 10000 U/min, switchable prescaler: 1 ... 1000
   Counter: -2.147.483.647 … 2.147.483.646
Supply voltage: 9 ... 28 V DC (standard)
Scope of supply: device, manual