User manual

to the TTL level (1.5 V) whenever the NI-DAQ driver is loaded. Any

changes you make will endure only for the life of the program.

Get_DAQ_Device_Info

In addition to its other functions, you can use Get_DAQ_Device_Info

to get the current input port threshold as shown in the following example:

err = Set_DAQ_Device_Info (device,

ND_DIO128_SELECT_INPUT_PORT, 3);

err = Get_DAQ_Device_Info (device,

ND_DIO128_GET_PORT_THRESHOLD, &port3threshold);

The value returned will be in millivolts.

LabVIEW VIs

Use the following LabVIEW VIs—DIO Port Config, DIO Port Read,

DIO Port Write, and DIO Parameter—to program the VXI-DIO-128

module.

DIO Port Config

• Ports 0–7 are input ports and ports 8–15 are output ports.

• Every line within a port must have the same direction (for instance,

all input or all output).

• The physical port width is 8 bits. You can combine up to four

consecutive ports into a 32-bit port.

DIO Port Read

• When the software reads the output lines, the returned data is simply

the last data written, and the returned status is the

badDirOnSomeLinesError warning.

DIO Port Write

You can write only to ports 8–15.

DIO Parameter

• You can use the GET operation on a particular input port to obtain

that port’s current logic threshold.

• You can use the SET operation on a particular input port to change

that port’s current logic threshold.