Key Digital ES381 - Manual (Page 5)

1 OVERVIEW
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
requires its own USB connection) 1
• 300V Cat II isolation between BNC ground and USB ground 2
This means that there is no DC path through the USBcount50
from the counters input to the PC’s 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