Counter/Timer Hardware Product-Feature Matrix


This document is part of a comprehensive tutorial on industrial Digital I/O and Counter/Timer hardware. Learn about National Instruments product offerings for digital and timing I/O, the Industrial Feature Set including watchdog timers and isolation, complementary devices like relays, solenoids and encoders, concepts like sinking and sourcing, and see how these devices can be used in your industrial application.

For more information return to the Complete Industrial Digital I/O and Counter/Timer Tutorial.

What are Counter/Timers?

The NI 660x and NI 661x counter/timers use the National Instruments NI-TIO, a National Instruments ASIC designed specifically to meet the counting and timing requirements of measurement applications that are beyond the capabilities of off-the-shelf components. The wider functionality and simpler programming interface make these devices ideal for counting and timing applications.

In addition to counter/timer functionality, the NI 660x and NI 661x devices include TTL-compatible digital I/O ports that are bit-configurable for input or output. These devices are suited for frequency measurement, generation of retriggerable pulses, frequency shift-keying, two-signal edge separation measurements, continuous buffered event counting, and continuous buffered pulse train measurements. The NI 660x and NI 661x counter/timer devices are readily integrated into measurement systems that require synchronization across multiple hardware devices because they are equipped with the National Instruments PXI Trigger bus or the RTSI bus.

In addition to the 660x and 661x boards, NI 6624 devices are industrial isolated timing interfaces for PCI bus computer systems. You can use the eight 32-bit channel-channel optically isolated counter/timers of the NI 6624 devices to perform a wide variety of buffered measurements or other counter/timer tasks, including position or quadrature encoder measurement, edge counting, period measurement, pulse-width measurement, frequency measurement, semi-period measurement, two-edge separation measurement, PWM generation, pulse, and pulse-train generation.

National Instruments Counter/Timer Hardware

Platforms PCI PXI PCI, PXI PCI PXI Express PXI Express
Counter Channels 8 8 8 4 8 8
Counter Resolution 32 32 bits 32 bits 32 bits 32 bits 32 bits
Isolation Ch-Ch Optically Isolated None None None None None
Standard Timebases 20 MHz 80 MHz, 80 MHz, 20 MHz, 100 MHz, 100 MHz
  100 kHz 20 MHz, 20 MHz, 100 kHz 20 MHz 20 MHz
    100 kHz 100 kHz   100 kHz 100 kHz
Timebase Stability 50 ppm 75 ppb 50 ppm 50 ppm 50 ppm 75 ppb
Prescalers none X8, X2 X8, X2 X8, X2 none none
Max Frequency (Without prescalers) 20 MHz 80 MHz 80 MHz 20 MHz 100 MHz 100 MHz
Max Frequency (With prescalers) N/A 125 MHz 125 MHz 60 MHz N/A N/A
Digital I/O 0 up to 32 bits up to 32 bits up to 32 bits up to 32 bits up to 32 bits
DMA (on board) 3 channels 3 channels 3 channels 1 channel 8 channels 8 channels
RTSI Bus (synchronize multi-board operation) Yes Yes Yes Yes Yes Yes
Updown counter (external control for counting direction) Yes Yes Yes Yes Yes Yes
Quadrature Motion Encoder Support Yes Yes Yes Yes Yes Yes
Debounce Filters on I/O Lines No Yes Yes Yes Yes Yes
Two-Signal Edge-Separation Measurement Yes Yes Yes Yes Yes Yes
Hardware Start Trigger Yes Yes Yes Yes Yes Yes
Start Counters Simultaneously Yes Yes Yes Yes Yes Yes
Continuous Buffered Input Yes Yes Yes Yes Yes Yes
Dynamic Pulse Train Frequency Change Yes Yes Yes Yes Yes Yes