daq.Channel Properties
Channel object properties
Alphabetical listing of channel object properties. The type of channel determines which of these properties a particular instance has.
Channel Properties
ActiveEdge
— Rising or falling edges of EdgeCount
signals
'Rising'
(default) | Falling
Rising or falling edges of the EdgeCount
signal,
specified as 'Rising'
or
'Falling'
.
Example: Create an
EdgeCount
counter channel, and set its
ActiveEdge
.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5',0,'EdgeCount')
ch = Data acquisition counter input edge count channel 'ctr0' on device 'Dev2': ActiveEdge: Rising CountDirection: Increment InitialCount: 0 Terminal: 'PFI8' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'EdgeCount'
Change the ActiveEdge
property to
'Falling'
:
ch.ActiveEdge = 'Falling'
ch = Data acquisition counter input edge count channel 'ctr0' on device 'Dev2': ActiveEdge: Falling CountDirection: Increment InitialCount: 0 Terminal: 'PFI8' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'EdgeCount'
Data Types: char
| string
ActivePulse
— Active pulse level for measurement of PulseWidth
counter channel
'High'
(default) | 'Low'
Pulse width measurement active level, specified as
'High'
or 'Low'
.
Example: Set active pulse level.
Create a session object, add a counter input channel, with the
'PulseWidth'
MeasurementType
.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5',0,'PulseWidth')
ch = Data acquisition counter input pulse width channel 'ctr0' on device 'cDAQ1Mod5': ActivePulse: High Terminal: 'PFI4' Name: empty ID: 'ctr1' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'PulseWidth'
Change the ActivePulse
property to
'Low'
.
ch.ActivePulse = 'Low'
ch = Data acquisition counter input pulse width channel 'ctr0' on device 'cDAQ1Mod5': ActivePulse: Low Terminal: 'PFI4' Name: empty ID: 'ctr1' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'PulseWidth'
Data Types: char
| string
ADCTimingMode
— Specify channel timing mode
char
Timing mode of all channels in the device. You can set the
ADCTimingMode
to:
'HighResolution'
'HighSpeed'
'Best50HzRejection'
'Best60HzRejection'
ADCTimingMode
must be the same for all channels on the
device.
Example: Set channel timing mode
Create a session and add an analog input channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod1','ai1','Voltage')
ch = Data acquisition analog input voltage channel 'ai1' on device 'cDAQ1Mod1': Coupling: DC TerminalConfig: SingleEnded Range: -10 to +10 Volts Name: '' ID: 'ai1' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Voltage' ADCTimingMode: ''
Set the ADCTimingMode
property to
'HighResolution'
.
ch.ADCTimingMode = 'HighResolution';
Data Types: char
| string
BridgeMode
— Specify analog input device bridge mode
char
Specify the bridge mode, which represents the active gauge of the analog
input channel. The default value is 'Unknown'
when you
add a bridge channel to the session. Change this value to a valid mode to
use the channel. Valid bridge modes are:
'Full'
— All four gauges are active.'Half'
— Only two bridges are active.'Quarter'
— Only one bridge is active.
Example
Set the BridgeMode
property of an
analog input bridge measurement type channel.
Create a session and add an analog input Bridge
channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod7',0,'Bridge');
Set the BridgeMode
property to
'Full'
and view the channel properties.
ch.BridgeMode = 'Full'
ch = Data acquisition analog input channel 'ai0' on device 'cDAQ1Mod7': BridgeMode: Full ExcitationSource: Internal ExcitationVoltage: 2.5 NominalBridgeResistance: 'Unknown' Range: -0.063 to +0.063 VoltsPerVolt Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Bridge' ADCTimingMode: HighResolution
Data Types: char
| string
CountDirection
— Specify direction of counter channel
'Increment'
(default) | 'Decrement'
Direction of the channel counter, specified as
'Increment'
(default) to count up, or
'Decrement'
, to count down.
Example
Create a session object, add a counter input channel, and change its
CountDirection
.
s = daq.createSession('ni'); ch = addCounterInputChannel (s,'cDAQ1Mod5', 0, 'EdgeCount')
ch = Data acquisition counter input edge count channel 'ctr0' on device 'cDAQ1Mod5': ActiveEdge: Rising CountDirection: Increment InitialCount: 0 Terminal: 'PFI8' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'EdgeCount'
Change CountDirection
to
'Decrement'
:
ch.CountDirection = 'Decrement'
ch = Data acquisition counter input edge count channel 'ctr0' on device 'cDAQ1Mod5': ActiveEdge: Rising CountDirection: Decrement InitialCount: 0 Terminal: 'PFI8' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'EdgeCount'
Data Types: char
| string
Coupling
— Input coupling mode
'DC'
| 'AC'
Coupling mode used for the analog input signal connection, specified as
'DC'
or 'AC'
. You cannot change
the value for devices that support only one mode. For devices that support
both AC and DC coupling, you can specify the mode by changing this property
value.
If
Coupling
is set to'DC'
, the signal input is connected directly to the amplifier, allowing measurement of the complete signal including its DC bias component. This is typically used with slowly changing signals such as temperature, pressure, or voltage readings.If
Coupling
is set to'AC'
, a series capacitor is inserted between the input connector and the amplifier, filtering out the DC bias component of the measured signal. This is typically used with dynamic signals such as audio.
Example
Create a session and add an analog input channel. Then change the coupling
mode to 'AC'
.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'Dev4','ai1','Voltage') ch.Coupling = 'AC'
Data Types: char
| string
Device
— Channel device information
DeviceInifo
object
This property is read-only.
Device information for the channel, returned as a
DeviceInfo
object.
Example
Create a session object, add a counter input channel, and view the channel
Device
property.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5',0,'EdgeCount'); ch.Device
ans = ni cDAQ1Mod5: National Instruments NI 9402 Counter input subsystem supports: Rates from 0.1 to 80000000.0 scans/sec 2 channels 'EdgeCount','PulseWidth','Frequency','Position' measurement types Counter output subsystem supports: Rates from 0.1 to 80000000.0 scans/sec 3 channels 'PulseGeneration' measurement type This module is in chassis 'cDAQ1', slot 5
Direction
— Specify digital channel direction
'Unknown'
(default) | 'Input'
| 'Output'
When you specify a digital channel MeasurementType
as
Bidirectional
, you can use the channel to input and
output data. By default the channel Direction
is set to
'Unknown'
. Other possible values are
'Input'
and 'Output'
.
Example: Change Bidirectional Channel Direction
Change the direction of a bidirectional digital channel
to Input
.
Create a session and add a bidirectional digital channel.
s = daq.createSession('ni') ch = addDigitalChannel(s, 'dev6', 'Port0/Line0', 'Bidirectional')
ch = Data acquisition digital bidirectional (unknown) channel 'port0/line0' on device 'Dev6': Direction: Unknown Name: '' ID: 'port0/line0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'Bidirectional (Unknown)'
Change the channel direction to 'Input'
. Note the
impact on the display of the channel description,
Direction
, and
MeasurementType
.
ch.Direction = 'Input'
ch = Data acquisition digital bidirectional (input) channel 'port0/line0' on device 'Dev6': Direction: Input Name: '' ID: 'port0/line0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'Bidirectional (Input)'
Data Types: char
| string
DutyCycle
— Duty cycle of output channel
numeric
Specify the fraction of time that the generated pulse is in active state.
Duty cycle is the ratio between the duration of the pulse and the pulse period. For example, if a pulse duration is 1 microsecond and the pulse period is 4 microseconds, the duty cycle is 0.25. In a square wave, the time the signal is high is equal to the time the signal is low, or duty cycle 0.5.
You can change the duty cycle of counter output channels while the session is running.
For function generation channels using Digilent devices, each waveform adopts the duty cycle.
Example
Create a session object and add a 'PulseGeneration'
counter output channel.
s = daq.createSession('ni'); ch = addCounterOutputChannel(s,'cDAQ1Mod5', 'ctr0', 'PulseGeneration')
ch = Data acquisition counter output pulse generation channel 'ctr0' on device 'cDAQ1Mod5': IdleState: Low InitialDelay: 2.5e-08 Frequency: 100 DutyCycle: 0.5 Terminal: 'PFI0' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'PulseGeneration'
Change the DutyCycle
to
0.25
.
ch.DutyCycle
ch = Data acquisition counter output pulse generation channel 'ctr0' on device 'cDAQ1Mod5': IdleState: Low InitialDelay: 2.5e-08 Frequency: 100 DutyCycle: 0.25 Terminal: 'PFI0' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'PulseGeneration'
EncoderType
— Encoding type of counter channel
'X1'
| 'X2'
| 'X4'
| 'TwoPulse'
Specify the encoding type of the counter input
'Position'
channel. Supported encoder types
include:
'X1'
'X2'
'X4'
'TwoPulse'
Example
Create a session and add a counter input channel with
Position
measurement type.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5', 'ctr0', 'Position')
ch = Data acquisition counter input position channel 'ctr0' on device 'cDAQ1Mod5': EncoderType: X1 ZResetEnable: 0 ZResetValue: 0 ZResetCondition: BothHigh TerminalA: 'PFI0' TerminalB: 'PFI2' TerminalZ: 'PFI1' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Position'
Change the channel encoder type to X2
.
ch.EncoderType = 'X2'
ch = Data acquisition counter input position channel 'ctr0' on device 'cDAQ1Mod5': EncoderType: X2 ZResetEnable: 0 ZResetValue: 0 ZResetCondition: BothHigh TerminalA: 'PFI0' TerminalB: 'PFI2' TerminalZ: 'PFI1' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Position
Data Types: char
| string
EnhancedAliasRejectionEnable
— Specify enhanced alias rejection mode
false
(default) | true
Enable or disable the enhanced alias rejection on your DSA device’s analog channel. See Synchronize DSA Devices for more information. Enhanced alias reject is disabled by default. This property only takes logical values.
You cannot modify enhanced rejection mode if you are synchronizing your DSA device using AutoSyncDSA.
Example: Enable enhanced alias rejection on a DSA device.
Create a session and add an analog input voltage channel using a DSA device.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'PXI1Slot2', 0, 'Voltage')
ch = Data acquisition analog input voltage channel 'ai0' on device 'PXI1Slot2': Coupling: DC TerminalConfig: PseudoDifferential Range: -42 to +42 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.PXIDSAModule] MeasurementType: 'Voltage' EnhancedAliasRejectionEnable: 0
Enable enhanced alias rejection.
ch.EnhancedAliasRejectionEnable = true
ch = Data acquisition analog input voltage channel 'ai0' on device 'PXI1Slot2': Coupling: DC TerminalConfig: PseudoDifferential Range: -42 to +42 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.PXIDSAModule] MeasurementType: 'Voltage' EnhancedAliasRejectionEnable: 1
Data Types: logical
ExcitationCurrent
— Current of external source of excitation
numeric
The current in amperes to excite an IEPE accelerometer, IEPE microphone, generic IEPE sensor, or RTD.
The default ExcitationCurrent
is typically determined
by the device. If the device supports a range of excitation currents, the
default is the lowest available value in the range.
Example: Change the excitation current value of a microphone channel
Create a session and add an analog input microphone
channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod3', 0, 'Microphone')
ch = Data acquisition analog input microphone channel 'ai0' on device 'cDAQ1Mod3': Sensitivity: 'Unknown' MaxSoundPressureLevel: 'Unknown' ExcitationCurrent: 0.002 ExcitationSource: Internal Coupling: AC TerminalConfig: PseudoDifferential Range: -5.0 to +5.0 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Microphone' ADCTimingMode: ''
Change the excitation current value to 4 milliamps.
ch.ExcitationCurrent = .004
ch = Data acquisition analog input microphone channel 'ai0' on device 'cDAQ1Mod3': Sensitivity: 'Unknown' MaxSoundPressureLevel: 'Unknown' ExcitationCurrent: 0.004 ExcitationSource: Internal Coupling: AC TerminalConfig: PseudoDifferential Range: -5.0 to +5.0 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Microphone' ADCTimingMode: ''
Data Types: double
ExcitationSource
— External source of excitation
'Unknown'
(default) | 'Internal'
| 'External'
| 'None'
The source of ExcitationVoltage for bridge measurements or ExcitationCurrent for IEPE sensors and RTDs. Excitation source can be:
Internal
External
None
Unknown
By default, ExcitationSource
is set to
'Unknown'
.
Example: Change the excitation source of a microphone channel
Create a session and add an analog input microphone
channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod3',0,'Microphone')
ch = Data acquisition analog input microphone channel 'ai0' on device 'cDAQ1Mod3': Sensitivity: 'Unknown' MaxSoundPressureLevel: 'Unknown' ExcitationCurrent: 0.004 ExcitationSource: Unknown Coupling: AC TerminalConfig: PseudoDifferential Range: -5.0 to +5.0 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Microphone' ADCTimingMode: ''
Change the excitation source value to
'Internal'
.
ch.ExcitationSource = 'Internal'
ch = Data acquisition analog input microphone channel 'ai0' on device 'cDAQ1Mod3': Sensitivity: 'Unknown' MaxSoundPressureLevel: 'Unknown' ExcitationCurrent: 0.004 ExcitationSource: Internal Coupling: AC TerminalConfig: PseudoDifferential Range: -5.0 to +5.0 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Microphone' ADCTimingMode: ''
Data Types: char
| string
ExcitationVoltage
— Voltage of excitation source
numeric
The excitation voltage value to apply to bridge measurements.
The default ExcitationVoltage
is typically determined
by the device. If the device supports a range of excitation voltages, the
default is the lowest available value in the range.
Data Types: double
Frequency
— Frequency of generated output
numeric
On counter output channels, use the Frequency
property to set the pulse repetition rate. You can change the channel
frequency while the session is running when using counter output
channels.
On function generation channels use the Frequency
property to specify the waveform frequency. You can set each channel
frequency individually.
The frequency value must fall within the specified FrequencyLimit values.
Example: Set the Frequency of a Counter Output Channel
Create a session object and add a 'PulseGeneration'
counter output channel:
s = daq.createSession('ni'); ch = addCounterOutputChannel(s,'cDAQ1Mod5', 'ctr0', 'PulseGeneration');
Change the Frequency
to
200
.
ch.Frequency = 200
ch = Data acquisition counter output pulse generation channel 'ctr0' on device 'cDAQ1Mod5': IdleState: Low InitialDelay: 2.5e-008 Frequency: 200 DutyCycle: 0.5 Terminal: 'PFI12' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'PulseGeneration'
Example: Set the Frequency of a Function Generator Channel
Create a waveform generation channel, and change the generation rate to 20000 scans per second.
s = daq.createSession('digilent'): fgenCh = addFunctionGeneratorChannel(s, 'AD1', 1, 'Sine'); fgenCh.Frequency = 20000
fgenCh = Data acquisition sine waveform generator '1' on device 'AD1': Phase: 0 Range: -5.0 to +5.0 Volts TerminalConfig: SingleEnded Gain: 1 Offset: 0 Frequency: 20000 WaveformType: Sine FrequencyLimit: [0.0 25000000.0] Name: '' ID: '1' Device: [1x1 daq.di.DeviceInfo] MeasurementType: 'Voltage'
Data Types: double
FrequencyLimit
— Limit of rate of operation based on hardware configuration
double array
This property is read-only.
The minimum and maximum rates that the function generation channel
supports. FrequencyLimit
changes dynamically as the
channel configuration changes.
Example
View the frequency limits of a waveform function generation channel.
s = daq.createSession('digilent') fgenCh = addFunctionGeneratorChannel(s, 'AD1', 1, 'Sine'); fgenCh.FrequencyLimit
ans = [0.0 25000000.0]
Data Types: double
Gain
— Waveform output gain
numeric
When using waveform function channels to generate standard waveforms,
Gain
sets the peak amplitude. For arbitrary
waveforms, Gain
prepresents the value by which the data
is multiplied to generate the output waveform.
The waveform gain can range from –5
to
5
. Be sure that for any instantaneous output point
Gain x Voltage + Offset
falls within the valid output
voltage range of the device.
Example
Change the gain of a waveform function generation channel for an amplitude of 2 volts.
s = daq.createSession('digilent'); fgenCh = addFunctionGeneratorChannel(s, 'AD1', 1, 'Sine'); fgenCh.Gain = 2
fgenCh = Data acquisition sine waveform generator '1' on device 'AD1': Phase: 0 Range: -5.0 to +5.0 Volts TerminalConfig: SingleEnded Gain: 2 Offset: 0 Frequency: 4096 WaveformType: Sine FrequencyLimit: [0.0 25000000.0] Name: '' ID: '1' Device: [1x1 daq.di.DeviceInfo] MeasurementType: 'Voltage'
Data Types: double
ID
— Channel identifier
char | string
This property is read-only.
Identifier of the channel, returned as a character array. The ID specifies a particular channel in the device subsystem. Use the channel ID when you add the channel to a session object.
Example
Create a session object, and add a counter input channel with the ID
'ctr0'
.
s = daq.createSession('ni'); ch = addCounterInputChannel (s,'cDAQ1Mod5', 'ctr0', 'EdgeCount')
ch= Data acquisition counter input edge count channel 'ctr0' on device 'cDAQ1Mod5': ActiveEdge: Rising CountDirection: Increment InitialCount: 0 Terminal: 'PFI8' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'EdgeCount'
Data Types: char
| string
IdleState
— Default state of counter output channel
'Low'
(default) | 'High'
Default state of the counter output channel with a
'PulseGeneration'
measurement type, when the counter
is not active, specified as 'Low'
or
'High'
.
Example
Create a session object and add a 'PulseGeneration'
counter output channel.
s = daq.createSession('ni'); ch = s.addCounterOutputChannel('cDAQ1Mod5', 'ctr0', 'PulseGeneration');
Change the IdleState
property to
'High'
.
ch.IdleState = 'High'
ans = Data acquisition counter output pulse generation channel 'ctr0' on device 'cDAQ1Mod5': IdleState: High InitialDelay: 2.5e-008 Frequency: 100 DutyCycle: 0.5 Terminal: 'PFI12' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'PulseGeneration'
Data Types: char
| string
InitialCount
— Specify initial count point
0 (default) | numeric
Point from which the device starts the counter, specified as a numeric value.
Example
Create a session object and add a counter input channel.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5',0,'EdgeCount')
ch = Data acquisition counter input edge count channel 'ctr0' on device 'cDAQ1Mod5': ActiveEdge: Rising CountDirection: Increment InitialCount: 0 Terminal: 'PFI8' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'EdgeCount'
Change the InitialCount
value to
15
.
ch.InitialCount = 15
ch = Data acquisition counter input edge count channel 'ctr0' on device 'cDAQ1Mod5': ActiveEdge: Rising CountDirection: Increment InitialCount: 15 Terminal: 'PFI8' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'EdgeCount'
InitialDelay
— Time delay until output channel generates pulses
numeric
Delay before counter output channel generates pulses, specified in seconds.
Example
Set the initial delay on a counter output channel to
3
seconds.
Create a session and add a counter output channel.
s = daq.createSession('ni'); ch = addCounterOutputChannel(s,'cDAQ1Mod5','ctr0','PulseGeneration');
Set the initial delay.
ch.InitialDelay = 3
ch = Data acquisition counter output pulse generation channel 'ctr0' on device 'cDAQ1Mod5': IdleState: Low InitialDelay: 3 Frequency: 100 DutyCycle: 0.5 Terminal: 'PFI0' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'PulseGeneration'
MaxSoundPressureLevel
— Sound pressure level for microphone channels
numeric
Specify the maximum sound pressure of the microphone channel in decibels.
The maximum sound pressure level is based on the sensitivity and the voltage
range of your device. When you set your device Sensitivity, the
MaxSoundPressureLevel
value is automatically
corrected to match the specified sensitivity value and the device voltage
range. You can also specify any acceptable pressure level in decibels. Refer
to your microphone specifications for more information.
Example
Change the Sensitivity
of a microphone
channel and set the maximum sound pressure level to 10.
Create a session and add a microphone channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod3', 0, 'Microphone')
ch = Data acquisition analog input microphone channel 'ai0' on device 'cDAQ1Mod3': Sensitivity: 'Unknown' MaxSoundPressureLevel: 'Unknown' ExcitationCurrent: 0.002 ExcitationSource: Internal Coupling: AC TerminalConfig: PseudoDifferential Range: -5.0 to +5.0 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Microphone' ADCTimingMode: ''
Set the channel Sensitivity
to
0.037
.
ch.Sensitivity = 0.037
ch = Data acquisition analog input microphone channel 'ai0' on device 'cDAQ1Mod3': Sensitivity: 0.037 MaxSoundPressureLevel: 136 ExcitationCurrent: 0.002 ExcitationSource: Internal Coupling: AC TerminalConfig: PseudoDifferential Range: -135 to +135 Pascals Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Microphone' ADCTimingMode: ''
Set the channel maximum sound pressure to 10 dB.
ch.MaxSoundPressureLevel = 10
ch = Data acquisition analog input microphone channel 'ai0' on device 'cDAQ1Mod3': Sensitivity: 0.037 MaxSoundPressureLevel: 10 ExcitationCurrent: 0.002 ExcitationSource: Internal Coupling: AC TerminalConfig: PseudoDifferential Range: -135 to +135 Pascals Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Microphone' ADCTimingMode: ''
MeasurementType
— Channel measurement type
char
This property is read-only.
Specified measurement type for the channel. Some channels support many measurement types:
Counter measurement types include:
'EdgeCount'
(input)'PulseWidth'
(input)'Frequency'
(input)'Position'
(input)'PulseGeneration'
(output)
Analog measurement types include:
'Voltage'
(input and output)'Thermocouple'
(input)'Current'
(input and output)'Accelerometer'
(input)'RTD'
(input)'Bridge'
(input)'Microphone'
(input)'IEPE'
(input)
Example
Create a session object, add a counter input channel with an
'EdgeCount'
MeasurementType
.
s = daq.createSession('ni'); ch = addCounterInputChannel (s, 'cDAQ1Mod5', 0, 'EdgeCount')
ch = Data acquisition counter input edge count channel 'ctr0' on device 'cDAQ1Mod5': ActiveEdge: Rising CountDirection: Increment InitialCount: 0 Terminal: 'PFI8' Name: empty ID: 'ctr0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'EdgeCount'
Data Types: char
Name
— Descriptive name for channel
char | string
Descriptive name for the channel, specified as a character vector or
string. By default there is no name assigned to a channel. You can change
the value of Name
at any time.
Example
Create a session and add an analog input channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'Dev1', 0, 'Voltage')
ch = Data acquisition analog input voltage channel 'ai0' on device 'Dev1': Coupling: DC TerminalConfig: Differential Range: -10 to +10 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'Voltage'
Change the channel Name
to
'AI-Voltage'
.
ch.Name = 'AI-Voltage'
ch = Data acquisition analog input voltage channel 'ai0' on device 'Dev1': Coupling: DC TerminalConfig: Differential Range: -10 to +10 Volts Name: 'AI-Voltage' ID: 'ai0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'Voltage'
Data Types: char
| string
NominalBridgeResistance
— Resistance of sensor
numeric
Resistance of a bridge based sensor, specified in ohms. This value is used to calculate voltage.
You can specify any accepted positive value in ohms. The default value is
0
, until you change it. You must set the resistance
to use the channel.
Offset
— DC offset of waveform
numeric
When using waveform function generation channels,
Offset
specifies the DC offset voltage of a signal
from zero, or the mean value of the waveform.
The waveform offset can be from –5
to
5
volts. Be sure that Gain x Voltage +
Offset
falls within the valid range of output voltage of the
device.
Example
Change the offset of the waveform function generation channel to 2 volts.
s = daq.createSession('digilent'); fgenCh = addFunctionGeneratorChannel(s, 'AD1', 1, 'Sine'); fgenCh.Offset = 2
fgenCh = Data acquisition sine waveform generator '1' on device 'AD1': Phase: 0 Range: -5.0 to +5.0 Volts TerminalConfig: SingleEnded Gain: 0 Offset: 2 Frequency: 4096 WaveformType: Sine FrequencyLimit: [0.0 25000000.0] Name: '' ID: '1' Device: [1x1 daq.di.DeviceInfo] MeasurementType: 'Voltage'
Phase
— Waveform phase shift
numeric
In a function generation channel, the Phase
property
specifies the waveform phase shift in degrees.
Example
Set the phase shift of a waveform function generation channel to 90°.
s = daq.createSession('digilent'); fgenCh = addFunctionGeneratorChannel(s, 'AD1', 1,'Sine'); fgenCh.Phase = 90
fgenCh = Data acquisition sine waveform generator '1' on device 'AD1': Phase: 90 Range: -5.0 to +5.0 Volts TerminalConfig: SingleEnded Gain: 1 Offset: 0 Frequency: 4096 WaveformType: Sine FrequencyLimit: [0.0 25000000.0] Name: '' ID: '1' Device: [1x1 daq.di.DeviceInfo] MeasurementType: 'Voltage'
R0
— RTD channel resistance value at 0°C
numeric
Specify the 0° resistance of the device in ohms. When you add an RTD
channel, the resistance is initially unknown and the R0
property displays Unknown
. Before any measurement, you
must change this value to correspond to the resistance of the device. For
more information, see https://en.wikipedia.org/wiki/Resistance_thermometer.
Example
Create a session and add an RTD channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod7',3,'RTD');
For a standard 100Ω probe, change the channel 0° resistance to 100Ω.
ch.R0 = 100
ch = Data acquisition analog input RTD channel 'ai3' on device 'cDAQ1Mod7': Units: Celsius RTDType: Unknown RTDConfiguration: Unknown R0: 100 ExcitationCurrent: 0.0005 ExcitationSource: Internal Coupling: DC TerminalConfig: Differential Range: -200 to +660 Celsius Name: '' ID: 'ai3' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'RTD' ADCTimingMode: HighResolution
Range
— Channel measurement range
numeric vector
Specify the measurement range of a channel, as a vector of numeric values.
For analog channels, the value is dependent on the measurement type. This
property is read-only for all measurement types except
'Voltage'
. You can specify a range in volts for
analog channels. Range
is not applicable for counter
channels.
Example: Specify the range of an analog input voltage channel
Create a session and add an analog input channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod7',3,'voltage');
Set a range of -60 to +60 volts.
ch.Range = [-60, 60];
Example: Examine supported ranges
Create a session and add an analog input channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'Dev1',3,'voltage');
Display the channel device.
ch.Device
ans = ni: National Instruments USB-6211 (Device ID: 'Dev1') Analog input subsystem supports: 4 ranges supported Rates from 0.1 to 250000.0 scans/sec 16 channels ('ai0' - 'ai15') 'Voltage' measurement type Analog output subsystem supports: -10 to +10 Volts range Rates from 0.1 to 250000.0 scans/sec 2 channels ('ao0','ao1') 'Voltage' measurement type Digital subsystem supports: 8 channels ('port0/line0' - 'port1/line3') 'InputOnly','OutputOnly' measurement types Counter input subsystem supports: Rates from 0.1 to 80000000.0 scans/sec 2 channels ('ctr0','ctr1') 'EdgeCount','PulseWidth','Frequency','Position' measurement types Counter output subsystem supports: Rates from 0.1 to 80000000.0 scans/sec 2 channels ('ctr0','ctr1') 'PulseGeneration' measurement type
View the device subsystems.
sub = ch.Device.Subsystems
sub = Analog input subsystem supports: 4 ranges supported Rates from 0.1 to 250000.0 scans/sec 16 channels ('ai0' - 'ai15') 'Voltage' measurement type Properties, Methods, Events Analog output subsystem supports: -10 to +10 Volts range Rates from 0.1 to 250000.0 scans/sec 2 channels ('ao0','ao1') 'Voltage' measurement type Properties, Methods, Events Digital subsystem supports: 8 channels ('port0/line0' - 'port1/line3') 'InputOnly','OutputOnly' measurement types Properties, Methods, Events Counter input subsystem supports: Rates from 0.1 to 80000000.0 scans/sec 2 channels ('ctr0','ctr1') 'EdgeCount','PulseWidth','Frequency','Position' measurement types Properties, Methods, Events Counter output subsystem supports: Rates from 0.1 to 80000000.0 scans/sec 2 channels ('ctr0','ctr1') 'PulseGeneration' measurement type Properties, Methods, Events
Display the ranges available on the analog input subsystem.
sub(1).RangesAvailable
ans = -0.20 to +0.20 Volts,-1.0 to +1.0 Volts,-5.0 to +5.0 Volts,-10 to +10 Volts
RTDConfiguration
— Specify wiring configuration of RTD device
'TwoWire'
| 'ThreeWire'
| 'FourWire'
When you create an RTD channel, the wiring configuration is unknown and
the RTDConfiguration
property displays
Unknown
. You must change this to one of the following
valid configurations:
TwoWire
ThreeWire
FourWire
Example: Specify an RTD channel wiring configuration
Create a session and add an RTD channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod7',3, 'RTD');
Change the RTDConfiguration
to
ThreeWire
.
ch.RTDConfiguration = 'ThreeWire'
ch = Data acquisition analog input RTD channel 'ai3' on device 'cDAQ1Mod7': Units: Celsius RTDType: Unknown RTDConfiguration: ThreeWire R0: 'Unknown' ExcitationCurrent: 0.0005 ExcitationSource: Internal Coupling: DC TerminalConfig: Differential Range: -200 to +660 Celsius Name: '' ID: 'ai3' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'RTD' ADCTimingMode: HighResolution
RTDType
— Specify sensor sensitivity
char | string
Specify the sensitivity of a standard RTD sensor. A standard RTD sensor is defined as a 100–ohm platinum sensor.
When you create an RTD channel, the sensitivity is unknown and the
RTDType
property displays
Unknown
. You must change this to one of these
supported values:
Pt3750
Pt3851
Pt3911
Pt3916
Pt3920
Pt3928
Example: Set an RTD sensor sensitivity type
Create a session and add an RTD channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod7',3,'RTD');
Set the RTDType
property to
Pt3851
.
ch.RTDType = 'Pt3851'
ch = Data acquisition analog input RTD channel 'ai3' on device 'cDAQ1Mod7': Units: Celsius RTDType: Pt3851 RTDConfiguration: ThreeWire R0: 'Unknown' ExcitationCurrent: 0.0005 ExcitationSource: Internal Coupling: DC TerminalConfig: Differential Range: -200 to +660 Celsius Name: '' ID: 'ai3' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'RTD' ADCTimingMode: HighResolution
Data Types: char
| string
Sensitivity
— Sensitivity of an analog channel
numeric
Specify the accelerometer or microphone sensor channel sensitivity.
Sensitivity in an accelerometer channel is expressed as volts per g-force, V/g.
Sensitivity in a microphone channel is expressed as volts per pascal, V/Pa.
Example
Create a session object, add an analog input channel, with a
MeasurementType
of
'accelerometer'
.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s ,'Dev4', 'ai0', 'accelerometer')
s = Data acquisition session using National Instruments hardware: Will run for 1 second (2000 scans) at 2000 scans/second. Number of channels: 1 index Type Device Channel MeasurementType Range Name ----- ---- ------ ------- -------------------------- ------------------ ---- 1 ai Dev4 ai0 Accelerometer (PseudoDiff) -5.0 to +5.0 Volts
Change the channel Sensitivity
to 10.2e-3 V/g:
ch.Sensitivity = 10.2e-3
s = Data acquisition session using National Instruments hardware: Will run for 1 second (2000 scans) at 2000 scans/second. Number of channels: 1 index Type Device Channel MeasurementType Range Name ----- ---- ------ ------- -------------------------- ---------------------- ---- 1 ai Dev4 ai0 Accelerometer (PseudoDiff) -490 to +490 Gravities
ShuntLocation
— Specify location of channel shunt resistor
'Internal'
| 'External'
On an analog input current channel, specify if the shunt resistor is
located internally on the device or externally with a property value of
'Internal'
or 'External'
.
If your device supports an internal shunt resistor, this property is set
to Internal
by default. If the shunt location is
external, you must specify the shunt resistance value.
Example
Set the shunt location of an analog input current channel.
Create a session and add an analog input current channel.
s = daq.createSession('ni') ch = addAnalogInputChannel(s,'cDAQ1Mod7',0,'Current');
Set the ShuntLocation
to
Internal
.
ch.ShuntLocation = 'Internal'
ch = Data acquisition analog input current channel 'ai0' on device 'cDAQ1Mod7': ShuntLocation: Internal ShuntResistance: 20 Coupling: DC TerminalConfig: Differential Range: -0.025 to +0.025 A Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Current' ADCTimingMode: HighResolution
Data Types: char
| string
ShuntResistance
— Resistance of channel shunt resistor
numeric
Analog input current channel resistance in ohms. This value is automatically set if the shunt resistor is located internally on the device and is read-only.
Before starting an analog output channel with an external shunt resistor, specify the shunt resistance value.
Example
Set the shunt resistance of an analog input current channel.
Create a session and add an analog input current channel.
s = daq.createSession('ni') ch = addAnalogInputChannel(s,'cDAQ1Mod7',0,'Current');
Set the ShuntLocation
to External
,
and the ShuntResistance
to 20
ohms.
ch.ShuntLocation = 'External';
ch.ShuntResistance = 20
ch = Data acquisition analog input current channel 'ai0' on device 'cDAQ1Mod7': ShuntLocation: External ShuntResistance: 20 Coupling: DC TerminalConfig: Differential Range: -0.025 to +0.025 A Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Current' ADCTimingMode: HighResolution
Terminal
— PFI terminal of counter subsystem
char
This property is read-only.
The Terminal
property indicates the counter
subsystem’s corresponding PFI terminal.
Example: Determine Counter Input Channel Terminal
Create a session and add a counter input channel.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5','ctr0','PulseWidth');
Examine the Terminal
property of the channel.
ch.Terminal
ans = PFI1
TerminalConfig
— Specify terminal configuration
char | string
Use the TerminalConfig
property to specify the
configuration of your analog channel. The property displays the hardware
default configuration. You can change this to one of the following:
SingleEnded
SingleEndedNonReferenced
Differential
PseudoDifferential
Example: Change the terminal configuration of an analog input channel
Create a session and add an analog input voltage channel.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'dev5',0,'voltage')
ch = Data acquisition analog input voltage channel 'ai0' on device 'Dev5': Coupling: DC TerminalConfig: Differential Range: -10 to +10 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'Voltage'
Change the channel TerminalConfig
property to
SingleEnded
.
ch.TerminalConfig = 'SingleEnded'
ch = Data acquisition analog input voltage channel 'ai0' on device 'Dev5': Coupling: DC TerminalConfig: SingleEnded Range: -10 to +10 Volts Name: '' ID: 'ai0' Device: [1x1 daq.ni.DeviceInfo] MeasurementType: 'Voltage'
Data Types: char
| string
ThermocoupleType
— Specify thermocouple type
char | string
Specify the type of thermocouple you used in making your measurements. Select the type based on the temperature range and sensitivity you need, according to the NIST Thermocouple Types Definitions.
Supported ThermocoupleType
values are:
'J'
'K'
'N'
'R'
'S'
'T'
'B'
'E'
By default the thermocouple type is 'Unknown'
.
Example
Create a session and add an analog input channel with
'Thermocouple'
measurement type.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod6','ai1','Thermocouple')
ch = Data acquisition analog input thermocouple channel 'ai1' on device 'cDAQ1Mod6': Units: Celsius ThermocoupleType: Unknown Range: -210 to +1200 Celsius Name: '' ID: 'ai1' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Thermocouple' ADCTimingMode: HighResolution
Set the ThermocoupleType
property to
'J'
.
ch.Thermocoupletype = 'J'
ch = Data acquisition analog input thermocouple channel 'ai1' on device 'cDAQ1Mod6': Units: Celsius ThermocoupleType: J Range: -210 to +1200 Celsius Name: '' ID: 'ai1' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Thermocouple' ADCTimingMode: HighResolution
Data Types: char
| string
Units
— Specify unit of RTD measurement
'Celsius'
(default) | 'Fahrenheit'
| 'Kelvin'
| 'Rankine'
Specify the temperature unit of the analog input channel with RTD measurement type. Supported temperature units are:
Celsius
(Default)Fahrenheit
Kelvin
Rankine
Example
Set the unit of an RTD channel.
Create a session, add an analog input RTD channel, and display channel properties.
s = daq.createSession('ni'); ch = addAnalogInputChannel(s,'cDAQ1Mod7', 0, 'RTD')
ch = Data acquisition analog input RTD channel 'ai0' on device 'cDAQ1Mod7': Units: Celsius RTDType: Unknown RTDConfiguration: Unknown R0: 'Unknown' ExcitationCurrent: 0.0005 ExcitationSource: Internal Coupling: DC TerminalConfig: Differential Range: -200 to +660 Celsius Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'RTD' ADCTimingMode: HighResolution
Change the Units
property from
Celsius
to Fahrenheit
Notice the
impact on the Range
property value.
ch.Units = 'Fahrenheit'
ch = Data acquisition analog input RTD channel 'ai0' on device 'cDAQ1Mod7': Units: Fahrenheit RTDType: Unknown RTDConfiguration: Unknown R0: 'Unknown' ExcitationCurrent: 0.0005 ExcitationSource: Internal Coupling: DC TerminalConfig: Differential Range: -328 to +1220 Fahrenheit Name: '' ID: 'ai0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'RTD' ADCTimingMode: HighResolution
Data Types: char
| string
WaveformType
— Function generator channel waveform type
char
This property is read-only.
Indicate the channel waveform type that was specified when the function generator channel was created. Supported waveform types are:
'Sine'
'Square'
'Triangle'
'RampUp'
'RampDown'
'DC'
'Arbitrary'
Display the channel waveform type.
fgenCh.WaveformType
ans = Sine
Data Types: char
ZResetCondition
— Reset condition for Z-indexing
char | string
Specify reset conditions for Z-indexing of counter Input
'Position'
channels. Supported values are:
'BothHigh'
'BothLow'
'AHigh'
'BHigh'
Example: Specify Counter Channel Z Reset Condition
Create a session and add a counter input 'Position'
channel.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5',0,'Position')
ch = Data acquisition counter input position channel 'ctr0' on device 'cDAQ1Mod5': EncoderType: X1 ZResetEnable: 0 ZResetValue: 0 ZResetCondition: BothHigh TerminalA: 'PFI0' TerminalB: 'PFI2' TerminalZ: 'PFI1' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Position'
Change the channel ZResetCondition
to
'BothLow'
.
ch.ZResetCondition = 'BothLow'
ch = Data acquisition counter input position channel 'ctr0' on device 'cDAQ1Mod5': EncoderType: X1 ZResetEnable: 0 ZResetValue: 0 ZResetCondition: BothLow TerminalA: 'PFI0' TerminalB: 'PFI2' TerminalZ: 'PFI1' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Position'
Data Types: char
| string
ZResetEnable
— Enable reset for Z-indexing
false
(default) | true
Allow the Z-indexing to be reset on a counter input
'Position'
channel, specified as
false
or true
.
Example: Reset Z Indexing on Counter Channel
Create a session and add a counter input 'Position'
channel.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5',0,'Position')
ch = Data acquisition counter input position channel 'ctr0' on device 'cDAQ1Mod5': EncoderType: X1 ZResetEnable: 0 ZResetValue: 0 ZResetCondition: BothHigh TerminalA: 'PFI0' TerminalB: 'PFI2' TerminalZ: 'PFI1' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Position'
Change the ZResetEnable
property value to
true
.
ch.ZResetEnable = true
ch = Data acquisition counter input position channel 'ctr0' on device 'cDAQ1Mod5': EncoderType: X1 ZResetEnable: 1 ZResetValue: 0 ZResetCondition: BothHigh TerminalA: 'PFI0' TerminalB: 'PFI2' TerminalZ: 'PFI1' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Position'
Data Types: logical
ZResetValue
— Reset value for Z-indexing
numeric
Specify the reset value for Z-indexing on a counter input
'Position'
channel.
Example
Create a session and add a counter input 'Position'
channel.
s = daq.createSession('ni'); ch = addCounterInputChannel(s,'cDAQ1Mod5',0,'Position')
ch = Data acquisition counter input position channel 'ctr0' on device 'cDAQ1Mod5': EncoderType: X1 ZResetEnable: 0 ZResetValue: 0 ZResetCondition: BothHigh TerminalA: 'PFI0' TerminalB: 'PFI2' TerminalZ: 'PFI1' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Position'
Change the ZResetValue
to 62
. Notice
also the change in ZResetEnable
.
ch.ZResetValue = 62
ch = Data acquisition counter input position channel 'ctr0' on device 'cDAQ1Mod5': EncoderType: X1 ZResetEnable: 1 ZResetValue: 62 ZResetCondition: BothHigh TerminalA: 'PFI0' TerminalB: 'PFI2' TerminalZ: 'PFI1' Name: '' ID: 'ctr0' Device: [1x1 daq.ni.CompactDAQModule] MeasurementType: 'Position'
Version History
Introduced in R2010b
See Also
Topics
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