def main():
# Parameters for AoDevice.a_out_scan
low_channel = 0
high_channel = 0
voltage_range_index = 0 # Use the first supported range
samples_per_channel = 2000 # Two second buffer (sample_rate * 2)
sample_rate = 1000 # Hz
scan_options = ScanOption.CONTINUOUS
scan_flags = AOutScanFlag.DEFAULT
interface_type = InterfaceType.USB
daq_device = None
ao_device = None
scan_status = ScanStatus.IDLE
try:
# Get descriptors for all of the available DAQ devices.
devices = get_daq_device_inventory(interface_type)
number_of_devices = len(devices)
# Verify at least one DAQ device is detected.
if number_of_devices == 0:
raise Exception('Error: No DAQ devices found')
print('Found', number_of_devices, 'DAQ device(s):')
for i in range(number_of_devices):
print(' ',
devices[i].product_name,
' (',
devices[i].unique_id,
')',
sep='')
# Create a DaqDevice object from the first descriptor.
daq_device = DaqDevice(devices[0])
ao_device = daq_device.get_ao_device()
# Verify the specified DAQ device supports analog output.
if ao_device is None:
raise Exception(
'Error: The DAQ device does not support analog output')
# Verify the specified DAQ device supports hardware pacing for analog output.
ao_info = ao_device.get_info()
if not ao_info.has_pacer():
raise Exception(
'Error: The DAQ device does not support paced analog output')
descriptor = daq_device.get_descriptor()
print('\nConnecting to', descriptor.dev_string, '- please wait...')
# Establish a connection to the device.
daq_device.connect()
chan_string = str(low_channel)
num_channels = high_channel - low_channel + 1
if num_channels > 1:
chan_string = ' '.join((chan_string, '-', str(high_channel)))
# Select the voltage range
voltage_ranges = ao_info.get_ranges()
if voltage_range_index < 0:
voltage_range_index = 0
elif voltage_range_index >= len(voltage_ranges):
voltage_range_index = len(voltage_ranges) - 1
voltage_range = ao_info.get_ranges()[voltage_range_index]
# Create a buffer for output data.
out_buffer = create_float_buffer(num_channels, samples_per_channel)
# Fill the output buffer with data.
amplitude = 1.0 # Volts
offset = amplitude if voltage_range > 1000 else 0.0 # Set an offset if the range is unipolar
samples_per_cycle = int(sample_rate / 10.0) # 10 Hz sine wave
create_output_data(num_channels, samples_per_channel,
samples_per_cycle, amplitude, offset, out_buffer)
print('\n', descriptor.dev_string, 'ready')
print(' Function demonstrated: AoDevice.a_out_scan')
print(' Channel(s):', chan_string)
print(' Range:', voltage_range.name)
print(' Samples per channel:', samples_per_channel)
print(' Sample Rate:', sample_rate, 'Hz')
print(' Scan options:', display_scan_options(scan_options))
try:
input('\nHit ENTER to continue')
except (NameError, SyntaxError):
pass
# Start the output scan.
sample_rate = ao_device.a_out_scan(low_channel, high_channel,
voltage_range, samples_per_channel,
sample_rate, scan_options,
scan_flags, out_buffer)
system('clear')
print('Please enter CTRL + C to terminate the process\n')
print('Active DAQ device: ',
descriptor.dev_string,
' (',
descriptor.unique_id,
')\n',
sep='')
print(' Actual scan rate: ', sample_rate, 'Hz')
try:
while True:
# Get and display the scan status.
scan_status, transfer_status = ao_device.get_scan_status()
if scan_status != ScanStatus.RUNNING:
break
print(' Current scan count: ',
transfer_status.current_scan_count)
print(' Current total count:',
transfer_status.current_total_count)
print(' Current index: ',
transfer_status.current_index)
stdout.flush()
sleep(0.1)
# Clear the previous status before displaying the next status.
for line in range(3):
stdout.write(CURSOR_UP + ERASE_LINE)
except KeyboardInterrupt:
pass
except Exception as e:
print('\n', e)
finally:
if daq_device:
# Stop the scan.
if scan_status == ScanStatus.RUNNING:
ao_device.scan_stop()
# Disconnect from the DAQ device.
if daq_device.is_connected():
daq_device.disconnect()
# Release the DAQ device resource.
daq_device.release()
def main():
interface_type = InterfaceType.USB
output_channel = 0
daq_device = None
try:
# Get descriptors for all of the available DAQ devices.
devices = get_daq_device_inventory(interface_type)
number_of_devices = len(devices)
# Verify at least one DAQ device is detected.
if number_of_devices == 0:
raise Exception('Error: No DAQ device is detected')
print('Found', number_of_devices, 'DAQ device(s):')
for i in range(number_of_devices):
print(' ',
devices[i].product_name,
' (',
devices[i].unique_id,
')',
sep='')
# Create a DaqDevice object from the first descriptor.
daq_device = DaqDevice(devices[0])
ao_device = daq_device.get_ao_device()
# Verify the specified DAQ device supports analog output.
if ao_device is None:
raise Exception(
'Error: The DAQ device does not support analog output')
descriptor = daq_device.get_descriptor()
print('\nConnecting to', descriptor.dev_string, '- please wait...')
# Establish a connection to the device.
daq_device.connect()
ao_info = ao_device.get_info()
output_range = ao_info.get_ranges()[
0] # Select the first supported range.
print('\n', descriptor.dev_string, 'ready')
print(' Function demonstrated: AoDevice.a_out')
print(' Channel:', output_channel)
print(' Range:', output_range.name)
try:
input('\nHit ENTER to continue')
except (NameError, SyntaxError):
pass
system('clear')
print('Active DAQ device: ',
descriptor.dev_string,
' (',
descriptor.unique_id,
')\n',
sep='')
print('*Enter non-numeric value to exit')
try:
while True:
try:
# Get and set a user specified output value.
out_val = input(' Enter output value (V): ')
ao_device.a_out(output_channel, output_range,
AOutFlag.DEFAULT, float(out_val))
# Clear the previous input request before the next input request.
stdout.write(CURSOR_UP + ERASE_LINE)
except (ValueError, NameError, SyntaxError):
break
except KeyboardInterrupt:
pass
except Exception as e:
print('\n', e)
finally:
if daq_device:
# Disconnect from the DAQ device.
if daq_device.is_connected():
daq_device.disconnect()
# Release the DAQ device resource.
daq_device.release()
