National Instruments 777557-01 PXI Counter/Timer Module

The 777557-01, also called the PXI-6602, is a timing and digital I/O board that is intended to be used with PXI or compactPCI chassis and the PCI bus in PC-compatible computers. Using the National Instruments MITE PCI interface, this device allows for high-speed DMA controllers, PCI burst transfers, and bus-master operation for continuous, scatter-gather DMA without using the host computer's DMA resources.

When it comes to measuring encoder position, events, periods, pulse width, pulse train generation, and frequency, the 5 V, 8-Channel PXI Counter/Timer Module (777557-01) performs exceptionally well. Digital debouncing filters, TTL/CMOS compatible digital I/O, and eight counter/timers are just a few of its features. In complex applications, the module's efficiency and performance are improved by its ability to manage three high-speed DMA transfers simultaneously.

The 777557-01 requires between 0.5 and 1.5 A of power. The I/O connector (pin 1) has a maximum current of 1 A and a voltage range of +4.65 V to +5.25 V. Compatibility with TTL/CMOS, a high-Z power-on state with mild pull-downs, pull-down currents between 10 μA and 200 μA, and input impedance between 25 kΩ and 500 kΩ are some of the module's I/O properties. A 56 Ω onboard resistor and a 19 Ω TIO ASIC output impedance are combined to provide the requisite 75 Ω output impedance. Hysteresis is controlled by 300 mV Schmitt triggers.

With 32 channels and no handshaking required, the digital I/O facilitates static data transfer. With a maximum count of 4,294,967,295 and a resolution of 32 bits, eight up/down counter/timers are part of the timing I/O. Robust performance is guaranteed for a range of applications by allowing data transfers via interrupts or DMA (up to three channels).

The module's physical dimensions are 16.0 cm x 10.0 cm (6.3 in x 3.9 in), and it makes use of a female SCSI-II type I/O connector with 68 pins. The maximum working voltage falls under Measurement Category I and is ±11 V for channel-to-earth and ±22 V for channel-to-channel.