DAQ VXI-SC-1102 Manual de Instruções descarregar pdf (Página 35)

Chapter 2 Lab and 1200 Devices

DAQ Hardware Overview Guide 2-8 www.ni.com

Figure 2-2 shows the connections of the 8253-B Counter/Timer signals to

the device I/O connector.

Figure 2-2. Lab and 1200 Devices Counter/Timer Signal Connections

Each counter has a clock input, a gate input, and an output labeled CLK,

GAT, and OUT, respectively. The clock pin for counters B1 and B2 and the

gate and output pins for counter B0, B1, and B2 are on the Lab and 1200

device I/O connector.

1200 Device Acquisition Rate

All I/O operations for the DAQCard-1200, DAQPad-1200, and SCXI-1200

are interrupt driven.

Note If you are using the parallel port of your PC to communicate with the SCXI-1200 or

the DAQPad-1200, your acquisition rates will be limited by the type of parallel port you

have in your system (either a standard Centronics port or an Enhanced parallel port).

Because both devices have a 2,048-word-deep FIFO, you can acquire bursts of less than

2,048 samples at maximum speed. If you are using the serial port of your PC to

communicate with the SCXI-1200 in a Remote SCXI configuration, your acquisition rates

are limited by the serial port baud rate you are using.

I/O Connector

2 MHz

Source

GATB2

CLKB2

OUTB2

OUTB0

GATB0

CLKB0

GATB1

CLKB1

OUTB1

8253 Counter/Timer

Group B

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DAQ VXI-SC-1102 Manual de Instruções Página 35