Measurement Specialties USB-1616HS-2 manual Counters, Input sequencer, Counter specifications

USB-1616HS-2 User's Guide Specifications

Counters

Counter inputs can be scanned based on an internal programmable timer or an external clock source.

	Table 6. Counter specifications
Channels	4 independent
Resolution	32-bit
Input frequency	20 MHz maximum
Input signal range	-5 V to 10 V
Input characteristics	10 kΩ pull-up, 200 Ω 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 (APR)
Trigger sources and modes	See Table 8
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

Input sequencer

Analog, digital, and counter inputs can be scanned based on either an internal programmable timer or an external clock source.

Table 7. Input sequencer specifications

Input scan clock sources: two (see Note 4)	Internal, programmable:
	ƒ	Analog channels from 1 µs to 1 s in 20.83 ns steps.
	ƒ	Digital channels and counters from 250 ns to 1 s in 20.83 ns steps.
	External. TTL level input (APR):
	ƒ	Analog channels down to 1 µs minimum
	ƒ	Digital channels and counters down to 250 ns minimum
Programmable parameters per scan:	Programmable channels (random order), programmable gain
Depth	512 locations
Onboard channel-to-channel scan rate	Analog: 1 MHz maximum
	Digital: 4 MHz if no analog channels are enabled, 1 MHz with analog
	channels enabled
External input scan clock (APR) maximum	Analog: 1.0 MHz
rate	Digital: 4 MHz if no analog channels are enabled, 1 MHz with analog
	channels enabled
Clock signal range:	Logical zero: 0 V to 0.8 V
	Logical one: 2.4 V to 5.0 V
Minimum pulse width	50 ns high, 50 ns low

Note 4: The maximum scan clock rate is the inverse of the minimum scan period. The minimum scan period is equal to 1 µs times the number of analog channels. If a scan contains only digital channels, then the minimum scan period is 250 ns.

Some platforms can sustain clock rates up to 83.33 ns.

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