uldaq/examples/AInScan.c

/*
    UL call demonstrated:       	  ulAInScan()

    Purpose:                          Performs a continuous scan of the range
                                      of A/D input channels

    Demonstration:                    Displays the analog input data for the
                                      range of 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. Verify the analog input subsystem has a hardware pacer
    5. Call ulConnectDaqDevice() to establish a UL connection to the DAQ device
    6. Get the first supported analog range
    7. Call ulAInScan() to start the scan of A/D input channels
    8. Call ulAInScanStatus() to check the status of the background operation
    9. Display the data for each channel
    10. Call ulAInScanStop() to stop the background operation
    11. 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
#define MAX_SCAN_OPTIONS_LENGTH 256

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 that are used to acquire data
	int lowChan = 0;
	int highChan = 3;
	AiInputMode inputMode;
	Range range;
	int samplesPerChannel = 10000;
	double rate = 1000;
	ScanOption scanOptions = (ScanOption) (SO_DEFAULTIO | SO_CONTINUOUS);
	AInScanFlag flags = AINSCAN_FF_DEFAULT;

	int hasAI = 0;
	int hasPacer = 0;
	int numberOfChannels = 0;
	int index = 0;

	char inputModeStr[MAX_STR_LENGTH];
	char rangeStr[MAX_STR_LENGTH];
	char scanOptionsStr[MAX_SCAN_OPTIONS_LENGTH];

	int chanCount = 0;
	double* buffer = NULL;
	UlError err = ERR_NO_ERROR;

	int i = 0;
	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 device supports analog input
	err = getDevInfoHasAi(daqDeviceHandle, &hasAI);
	if (!hasAI)
	{
		printf("\nThe specified DAQ device does not support analog input\n");
		goto end;
	}

	// verify the specified device supports hardware pacing for analog input
	err = getAiInfoHasPacer(daqDeviceHandle, &hasPacer);
	if (!hasPacer)
	{
		printf("\nThe specified DAQ device does not support hardware paced 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;

	chanCount = highChan - lowChan + 1;

	// allocate a buffer to receive the data
	buffer = (double*) malloc(chanCount * samplesPerChannel * sizeof(double));

	if(buffer == 0)
	{
		printf("\nOut of memory, unable to create scan buffer\n");
		goto end;
	}

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

	ConvertScanOptionsToString(scanOptions, scanOptionsStr);

	printf("\n%s ready\n", devDescriptors[descriptorIndex].devString);
	printf("    Function demonstrated: ulAInscan()\n");
	printf("    Channels: %d - %d\n", lowChan, highChan);
	printf("    Input mode: %s\n", inputModeStr);
	printf("    Range: %s\n", rangeStr);
	printf("    Samples per channel: %d\n", samplesPerChannel);
	printf("    Rate: %f\n", rate);
	printf("    Scan options: %s\n", scanOptionsStr);
	printf("\nHit ENTER to continue\n");

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

	// clear the display
	ret = system("clear");

	// start the acquisition
	err = ulAInScan(daqDeviceHandle, lowChan, highChan, inputMode, range, samplesPerChannel, &rate, scanOptions, flags, buffer);

	if(err == ERR_NO_ERROR)
	{
		ScanStatus status;
		TransferStatus transferStatus;

		// get the initial status of the acquisition
		ulAInScanStatus(daqDeviceHandle, &status, &transferStatus);

		while(status == SS_RUNNING && err == ERR_NO_ERROR && !enter_press())
		{
			// get the current status of the acquisition
			err = ulAInScanStatus(daqDeviceHandle, &status, &transferStatus);

			// reset the cursor to the top of the display and
			// show the termination message
			resetCursor();
			printf("Hit 'Enter' to terminate the process\n\n");

			printf("actual scan rate = %f\n\n", rate);

			index = transferStatus.currentIndex;
			printf("currentScanCount =  %10llu \n", transferStatus.currentScanCount);
			printf("currentTotalCount = %10llu \n", transferStatus.currentTotalCount);
			printf("currentIndex =      %10d \n\n", index);

			// display the data
			for (i = 0; i < chanCount; i++)
			{
				printf("chan %d = %10.6f\n",
						i + lowChan,
						buffer[index + i]);
			}

			usleep(100000);
		}

		// stop the acquisition if it is still running
		if (status == SS_RUNNING && err == ERR_NO_ERROR)
		{
			err = ulAInScanStop(daqDeviceHandle);
		}
	}

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

end:

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

	// release the scan buffer
	if(buffer)
		free(buffer);

	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;
}