Key Digital ES381 User Manual

 
The USBcount50 is an isolated digital pulse counter that has the 
following features: 
  
•  Single channel pulse counter with BNC input and USB PC 

interface 

•  Each USBcount50 can be stacked to increase channel count (each 

•  300V Cat II isolation between BNC ground and USB ground

•  Up to 50MHz input counting, 100MHz with suitable input signal 
•  10ns timing resolution 
•  Single shot or continuous update 
•  28-bit counter gives 268 million : 1 dynamic range 
•  Two modes of operation: Frequency mode or Period mode 
•  Frequency mode can use 0.1s, 1s or 10s integration times.  Large 

dynamic range of counter means 1s integration setting can be 
used from 1KHz up to 100MHz i.e. no auto-ranging required 

•  Period mode can use internal 1MHz, 10MHz or 100MHz 

reference clocks coupled with edge detection logic for 
rising→rising, falling→falling, falling→rising, rising→falling.  
Large dynamic range of counter means 100MHz clock setting can 
be used from 10us up to 26.8s i.e. no auto-ranging required 

•  Period mode (aka reciprocal counting mode) is able to measure 

frequencies down to below 4mHz. 

•  Programmable input stage voltage level from 1.5V to 5.0V in 256 

steps 

•  Input protected to 30V DC 
•  Host powered from USB (200mA typ) 
•  Stacked configurations of 2,3 and 4 channels are supported 
•  Power/activity LED 
 
 

                                                 

1

 A stacking connector kit is required 

2

 In stacked configurations the channels share a common ground at the BNC terminals 

Elan Digital Systems Ltd.

 5 

 

USBcount50 USER’S GUIDE Iss1