Measurement Computing USB-1616HS-BNC, User Manual

Page: 43 / 49

USB-1616HS-BNC User's Guide Specifications
43
Digital input/output
Table 4. Digital input/output specifications
Number of I/O 16
Ports Two banks of eight.
Each port is programmable as input or output
Input scanning modes Two programmable
 Asynchronous, under program control at any time relative to input scanning
 Synchronous with input scanning
Input characteristics 220 Ω series resistors, 20 pF to common
Logic keeper circuit Holds the logic value to 0 or 1 when there is no external driver
Input protection ±15 kV ESD clamp diodes parallel
Input high +2.0 V to +5.0 V
Input low 0 to 0.8 V
Output high >2.0 V
Output low <0.8 V
Output current Output 1.0 mA per pin
Digital input pacing Onboard input scan clock, external input scan clock (XAPCR)
Digital output pacing Three programmable sources:

Onboard output scan clock, independent of input scan clock
 Onboard input scan clock
 External input scan clock (XAPCR)
Digital input trigger sources and
modes See Table 7
Digital output trigger sources Start of input scan
Sampling/update rate 4 MHz maximum (rates up to 12 MHz are sustainable on some platforms)
Pattern generation output Both 8-bit ports can be configured to support 16-bit pattern generation. The pattern
can also be updated synchronously with an acquisition at up to 4 MHz.
Counters
Counter inputs can be scanned based on an internal programmable timer or an external clock source.
Table 5. Counter specifications
Channels 4 independent
Resolution 32-bit
Input frequency 20 MHz maximum
Input signal range -5 V to 10 V
Input characteristics
10 k pull-up, 200 series resistor, ±15 kV ESD protection
Trigger level TTL
Minimum pulse width 25 ns high, 25 ns low
Debounce times 16 selections from 500 ns to 25.5 ms, positive or negative edge sensitive, glitch
detect mode or debounce mode
Time base accuracy 50 ppm (0 ° to 50 °C)
Counter read pacer Onboard input scan clock, external input scan clock (XAPCR)
Trigger sources and modes See Table 7
Programmable mode Counter
Counter mode options Totalize, clear on read, rollover, stop at all Fs, 16- or 32-bit, any other channel can
gate the counter