Measurement Computing USB-DIO24H/37 - Manual (Page 16)

USB-DIO24H/37 User's Guide Specifications
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Counter
Table 2. Counter specifications
Pin name (Note 4) CTR
Counter type Event counter
Number of channels 1
Input source CTR screw terminal
Input type TTL, rising edge triggered
Resolution 32 bits
Schmidt trigger hysteresis 20 mV to 100 mV
Input leakage current ±1 µA
Maximum input frequency 1 MHz
High pulse width 500 ns min
Low pulse width 500 ns min
Input low voltage 0 V min, 1.0 V max
Input high voltage 4.0 V min, 15.0 V max
Note 4: CTR is a Schmitt trigger input.
Data transfer rates
Table 3. Data transfer rate specifications
Digital I/O transfer rates (software paced)
Digital input 62 port reads or single bit reads per second (typical)
Digital output 125port writes or single bit writes per second (typical)
Counter/timer read/write rates (software paced)
Counter read 62 port reads per second (typical)
Counter clear 125 port writes per second (typical)
Power
Table 4. Power specifications
Parameter Conditions Specification
Supply current (Note 5) No Load 100mA typ, 135 mA max
Input power requirements (Note 6) 4.75 V min, 5.25 V max
USB +5 V power available Measured at "USB +5 V" screw
terminals (pins 10, 14, and 30) 4.4 V min, 5.25 V max
USB +5 V power
output current (Note 7)
Connected to:
 Self-powered hub
 Externally-powered root port hub [350 mA] – [total output source
current]
USB +5 V over-current protection Resettable fuse Hold current: 350 mA, typical
Trip current: 700 mA typical
Trip/recovery time: 100 mS, max
On resistance: 1.3 Ohms max
Note 5: This is the total (no load) current requirement for the USB-DIO24H/37.
Note 6: Bus-powered hubs are allowed to provide downstream USB power as low as 4.4 V. Although your
USB-DIO24H/37 will typically function at this 4.4 V minimum, guaranteed performance requires a
minimum power supply voltage of 4.75 V. All self-powered and root port hubs will meet this 4.75 V
minimum.