uldaq/examples/AIn.c

/*
    UL call demonstrated:        	  ulAIn()

    Purpose:                          Reads the user-specified A/D input channels

    Demonstration:                    Displays the analog input data for each of
                                      the user-specified channels using the first
                                      supported range and input mode

    Steps:
    1. Call ulGetDaqDeviceInventory() to get the list of available DAQ devices
    2. Call ulCreateDaqDevice() to to get a handle for the first DAQ device
    3. Verify the DAQ device has an analog input subsystem
    4. Call ulConnectDaqDevice() to establish a UL connection to the DAQ device
    5. Get the first supported analog range
    6. Call ulAIn() for each channel specified to read a value from the A/D input channel
    7. Display the data for each channel
    8. Call ulDisconnectDaqDevice() and ulReleaseDaqDevice() before exiting the process.
*/

#include <stdio.h>
#include <stdlib.h>
#include "uldaq.h"
#include "utility.h"

#define MAX_DEV_COUNT  100
#define MAX_STR_LENGTH 64

int main(void)
{
	int descriptorIndex = 0;
	DaqDeviceDescriptor devDescriptors[MAX_DEV_COUNT];
	DaqDeviceInterface interfaceType = ANY_IFC;
	DaqDeviceHandle daqDeviceHandle = 0;
	unsigned int numDevs = MAX_DEV_COUNT;

	// set some variables used to acquire data
	int lowChan = 0;
	int highChan = 3;
	int chan = 0;
	AiInputMode inputMode;
	Range range;
	AInFlag flags = AIN_FF_DEFAULT;

	int hasAI = 0;
	int numberOfChannels = 0;

	char inputModeStr[MAX_STR_LENGTH];
	char rangeStr[MAX_STR_LENGTH];

	int i = 0;
	double data = 0;
	UlError err = ERR_NO_ERROR;

	int __attribute__((unused)) ret;
	char c;

	// Get descriptors for all of the available DAQ devices
	err = ulGetDaqDeviceInventory(interfaceType, devDescriptors, &numDevs);
	
	if (err != ERR_NO_ERROR)
		goto end;

	// verify at least one DAQ device is detected
	if (numDevs == 0)
	{
		printf("No DAQ device is detected\n");
		goto end;
	}

	printf("Found %d DAQ device(s)\n", numDevs);
	for (i = 0; i < (int) numDevs; i++)
		printf("  %s: (%s)\n", devDescriptors[i].productName, devDescriptors[i].uniqueId);

	// get a handle to the DAQ device associated with the first descriptor
	daqDeviceHandle = ulCreateDaqDevice(devDescriptors[descriptorIndex]);

	if (daqDeviceHandle == 0)
	{
		printf ("\nUnable to create a handle to the specified DAQ device\n");
		goto end;
	}

	// verify the specified DAQ device supports analog input
	err = getDevInfoHasAi(daqDeviceHandle, &hasAI);
	if (!hasAI)
	{
		printf("\nThe specified DAQ device does not support analog input\n");
		goto end;
	}

	printf("\nConnecting to device %s - please wait ...\n", devDescriptors[descriptorIndex].devString);

	// establish a connection to the DAQ device
	err = ulConnectDaqDevice(daqDeviceHandle);

	if (err != ERR_NO_ERROR)
		goto end;

	// get the first supported analog input mode
	err = getAiInfoFirstSupportedInputMode(daqDeviceHandle, &numberOfChannels, &inputMode, inputModeStr);

	if (highChan >= numberOfChannels)
		highChan = numberOfChannels - 1;

	// get the first supported analog input range
	err = getAiInfoFirstSupportedRange(daqDeviceHandle, inputMode, &range, rangeStr);

	printf("\n%s ready\n", devDescriptors[descriptorIndex].devString);
	printf("    Function demonstrated: ulAIn()\n");
	printf("    Channels: %d - %d\n", lowChan, highChan);
	printf("    Input mode: %s\n", inputModeStr);
	printf("    Range: %s\n", rangeStr);
	printf("\nHit ENTER to continue\n");

	ret = scanf("%c", &c);

	ret = system("clear");

	while(err == ERR_NO_ERROR && !enter_press())
	{
		// reset the cursor to the top of the display and
		// show the termination message
		resetCursor();
		printf("Hit 'Enter' to terminate the process\n\n");

		// display data for the first 4 analog input channels
		for (chan = lowChan; chan <= highChan; chan++)
		{
			err = ulAIn(daqDeviceHandle, chan, inputMode, range, flags, &data);

			if(err == ERR_NO_ERROR)
				printf("Channel(%d) Data: %10.6f\n", chan, data);
		}

		usleep(100000);
	}

	// disconnect from the DAQ device
	ulDisconnectDaqDevice(daqDeviceHandle);

end:

	// release the handle to the DAQ device
	if(daqDeviceHandle)
		ulReleaseDaqDevice(daqDeviceHandle);

	if(err != ERR_NO_ERROR)
	{
		char errMsg[ERR_MSG_LEN];
		ulGetErrMsg(err, errMsg);
		printf("Error Code: %d \n", err);
		printf("Error Message: %s \n", errMsg);
	}

	return 0;
}