Counter/Timer

Comparison
BOARD	NI 6608	NI 6602	NI 6601	E Series
Platforms	PXI	PCI, PXI	PCI	PCI, PXI, ISA, PCMCIA, USB, 1394
Counter ASIC	NI-TIO	NI-TIO	NI-TIO	DAQ-STC
Counter Channels	8	8	4	2
Counter Resolution	32 bits	32 bits	32 bits	24 bits
Standard Timebases	80 MHz,	80 MHz,	20 MHz,	20 MHz,
	20 MHz,	20 MHz,	100 kHz	100 kHz
	100 kHz	100 kHz
Timebase Stability	75 ppb2	50 ppm1	50 ppm1	100 ppm1
Prescalers	X8, X2	X8, X2	X8, X2	none
Max External Source Frequency
Without prescalers	80 MHz	80 MHz	20 MHz	20 MHz
With prescalers	125 MHz	125 MHz	60 MHz	N/A
Digital I/O	up to 32 bits	up to 32 bits	up to 32 bits	8 bits
DMA (on board)3	3 channels	3 channels	1 channel	Up to 3 channels4
RTSI Bus (synchronize multi-board operation)	Yes	Yes	Yes	Depends on platform5
Updown counter (external control for counting direction)	Yes	Yes	Yes	Yes
Quadrature Motion Encoder Support	Yes	Yes	Yes	with external IC, channels A & B only
Debounce Filters on I/O Lines	Yes	Yes	Yes	No
Two-Signal Edge-Separation Measurement	Yes	Yes	Yes	No
Hardware Start Trigger	Yes	Yes	Yes	No
Start Counters Simultaneously	Yes	Yes	Yes	No
Continuous Buffered Input	Yes	Yes	Yes	Yes
Dynamic Pulse Train Frequency Change	Yes	Yes	Yes	Yes
Check Price	PXI-6608	PCI-6602 PXI-6602	PCI-6601	E-Series

^{1. The unit ppm denotes parts per million and indicates how much the frequency can deviate from the specified frequency - 50 ppm corresponds to 0.005%.}

^{2. The unit ppb denotes parts ber billion and indicates how much the frequency can deviate from the specified frequency. This stability is applicable over a period of one year. See NI 6608 product documentation for details.}

^{3. The number of DMA channels determines the number of simultaneous high speed data transfers. See data sheet for NI 660x products.}

^{4. The number of DMA channels for E Series devices depends on the device. Refer to specifications for E Series devices.}

^{5. All the AT and PCI E Series devices support the RTSI bus. All the PXI E Series devices support the PXI trigger bus.}