Earlier releases of NI-DAQ software included a translational table in order to assist users who were migrating from Traditional NI-DAQ (Legacy) to NI-DAQmx. This translational table also provided definitions for much of the terminology used by the DAQ software. As NI-DAQmx is now the standard, later releases of the help documentation omit this section.
Note: The following information used to be found in the NI-DAQmx Help.
The following tables translate terms from Traditional NI-DAQ (Legacy) to NI-DAQmx for both the C API and LabVIEW API.
| Traditional NI-DAQ C API | Traditional NI-DAQ LabVIEW | NI-DAQmx | Explanation |
| Sample Interval Counter (and Channel Clock) | Channel Clock or Interchannel Delay | AI Convert Clock | The E Series clock that directly causes analog-to-digital conversions |
| Points per Second (as Sample Rate) | Channels per Second | Conversions per Second | Units for specifying AI convert clock rate |
| Sample Timebase (and Channel Clock Timebase) | Timebase | AI Convert Clock Timebase | The clock that is divided down to produce the AI convert clock |
| Sample Interval | Timebase Divisor | AI Convert Clock Timebase Divisor | The number of AI convert timebase ticks used to divide down the AI convert timebase |
| Scan Interval Counter (and Scan Clock) | Scan Clock | Sample Clock | The clock that controls the time interval between samples. Each time the sample clock ticks (produces a pulse) one sample per channel is acquired. |
| Scans per Second (as scanRate) | Scans per Second | Samples per Channel per Second | Units for specifying sample acquisition rate (the sample rate) |
| Scan Timebase | Timebase | Sample Clock Timebase | The clock that is divided down to produce the sample clock |
| Scan Interval | Timebase Divisor | Sample Clock Timebase Divisor | The number of sample clock timebase ticks used to divide down the sample clock timebase |
| Start Trigger | Start Trigger | Start Trigger | The trigger that begins an acquisition |
| Stop Trigger | Stop Trigger | Reference Trigger | The trigger that creates the reference point between the pretrigger samples and the post-trigger samples |
| No Equivalent | Scan Clock Gating | Pause Trigger | The signal that pauses and resumes an acquisition |
| No Equivalent | ATCOUT | Analog Comparison Event | The signal from the analog comparator circuit, used most often for analog triggering |
| SCANCLK | SCANCLK | AI Hold Complete Event | A digital signal emitted by an E Series device when the analog signal about to be converted by the ADC has been held |
| Traditional NI-DAQ C API | Traditional NI-DAQ LabVIEW | NI-DAQmx | Explanation |
| Reading, Voltage, Sample | Sample | Sample | A single measurement from a single channel |
| Scan | Scan | No Equivalent | A set of samples, one from each channel in the task |
| Sample Count | Scans per buffer | Buffer Size (in Samples Per Channel) | Method for specifying the buffer size |
| No Equivalent — the Sequential parameter in DAQ_Monitor is the closest | Read/Search Mode | Position | Where to place the read position prior to adding the offset |
| No Equivalent | Read/Search Offset | Offset | After placing the read position, this offset is added to determine where the read takes place; all subsequent reads use this offset until the offset is changed |
| No Equivalent | Read Mark Scan | Current Sample Number | The current read position |
| No Equivalent | Scan Backlog | Available Samples Per Channel | The amount of unread data in the buffer |
| Retrieved | End of Data Scan | Total Samples Per Channel Acquired | The total number of samples acquired into the buffer |
| Count | Total Scans to Acquire | Samples per Channel | The total number of samples to acquire |
| numPts | Number to Read | Number of Samples per channel | The number of samples to read |
| Traditional NI-DAQ | NI-DAQmx | Explanation |
| 0,1, and so on | Dev1/ai0, Dev1/ai1, and so on | In Traditional NI-DAQ, physical channel names were numbers. In NI-DAQmx, physical channels are string names that combine the device name, the I/O type, and the physical channel number |
| Traditional NI-DAQ C API | Traditional NI-DAQ LabVIEW | NI-DAQmx | Explanation |
| Update Clock | Update Clock | Sample Clock | The clock that causes D/A conversions |
| Updates per Second | Updates per Second | Samples per Channel per Second | Units for Specifying digital-to-analog conversion (DAC) rate |
| Timebase | Timebase | Sample Clock Timebase | The clock that is divided down to product the sample clock |
| Interval | Timebase Divisor | Sample Clock Timebase Divisor | The number of sample clock timebase ticks used to divide down the sample clock timebase |
| Start Trigger | Start Trigger | Start Trigger | The trigger that begins a generation |
| No Equivalent | Gate | Pause Trigger | The signal that pauses and resumes a generation |
| Traditional NI-DAQ C API | Traditional NI-DAQ LabVIEW | NI-DAQmx | Explanation |
| Voltage, Sample | Update | Sample | A single measurement generated at a single channel |
| No Equivalent | Update | No Equivalent | A set of samples, one for each channel in the task |
| No Equivalent | Write Mode | Position | Where to place the write position prior to adding the offset |
| No Equivalent | Write Offset | Offset | After placing the write position, this offset is added to determine where the write will take place. All subsequent writes will use this offset until the offset is changed |
| No Equivalent | Write Mark | Current Sample Number | The place in the buffer where the next write begins if the Position property/attribute is Relative to Current Write Position and the Offset property/attribute is 0 |
| No Equivalent | No Equivalent | Space Available in Buffer | The number of samples that can be written without overwriting a sample that has not been output |
| pointsDone, itersDone | Output Mark, Buffer Iterations | Total Samples Per Channel Generated | The total number of samples that have been written to the device; although the samples have been written to the device, they may not have been generated yet |
| oldDataStop | Regeneration Mode | Regeneration | The property/attribute that controls whether old data is regenerated |
| partialTransfer | Regeneration Mode | No Equivalent | To stop a waveform generation after a specific number of samples are generated, set the NI-DAQmx property/attribute samples per channel to the desired number of samples |
| Iterations | Iterations | Samples per Channel | To generate a finite number of iterations of a buffer, set the samples per channelproperty/attribute to I × N, where I is the desired number of iterations, and N is the number of samples per channel in the buffer. |
| Traditional NI-DAQ | NI-DAQmx | Explanation |
| 0,1, and so on | Dev1/ao0, Dev1/ao1, and so on | In Traditional NI-DAQ, physical channel names were numbers. In NI-DAQmx, physical channels are string names that combine the device name, the I/O type, and the physical channel number |
| Traditional NI-DAQ C API | Traditional NI-DAQ LabVIEW | NI-DAQmx | Explanation |
| Start Trigger | Start Trigger | Start Trigger | The signal that begins a counter operation |
| Gate | Gate | Pause Trigger | The signal that pauses and resumes a counter operation |
| Traditional NI-DAQ C API | Traditional NI-DAQ LabVIEW | NI-DAQmx | Explanation |
| Event Counting | Event Counting | Edge Counting | A counter tallies the total number of rising or falling edges |
| No Equivalent | Frequency Shift Keying | NI-DAQmx does not support Frequency Shift Keying |
|
| Traditional NI-DAQ | NI-DAQmx | Explanation |
| 0, 1, and so on | Dev1/ctr0, Dev1/ctr1, and so on | In Traditional NI-DAQ, physical channel names were numbers. In NI-DAQmx, physical channels are string names that combine the device name, the I/O type, and the physical channel number |
| Traditional NI-DAQ | NI-DAQmx | Explanation |
| 0, 1, as port | Dev1/port0, Dev1/port1, and so on | In Traditional NI-DAQ, physical channel names were numbers. In NI-DAQmx, physical channels are string names that combine the device name, the I/O type, and the physical channel number. If the line number is omitted from the NI-DAQmx name, all lines in the port are included. |
| 0, 1 as line | Dev1/port0/line0, Dev1/port0/line1 | When the line number is present in the NI-DAQmx name, only that line is meant |
| No Equivalent | Dev1/port1_16 | Concatenated ports, porta_b, where a is the port number of the beginning port and b is the width in lines |
Notes:
Channel list (scan list)
List of channels to be sampled.
Scan
A set of samples, one from each channel in the channel list.
Interval scanning
A multi-channel sampling method. This method uses the sample (scan) clock to control when a scan begins and uses the convert (channel) clock to control when each channel in the channel list is sampled.
Sample/Sampling rate (scan rate)
The rate at which one sample per channel is acquired; the rate at which the sample (scan) clock is set. Note that the maximum sampling rate specification for our E Series data acquisition boards refers to the maximum rate at which a single channel can be acquired. For example, the PCI-6071E is capable of a 1.25 MS/s sampling rate. This may consist of 1.25 MS/s on one channel or 250 kS/s on five channels.
Units: Samples per Channel per Second (Scans per Second)
Convert rate (channel rate)
The rate at which the analog-to-digital conversions occur; the rate at which the convert (channel) clock is set.
Units: Conversions per Second (Channels per Second)
Interchannel delay
The amount of time which passes between sampling consecutive channels in the channel list. The convert rate is the reciprocal of the interchannel delay. The interchannel delay must be short enough to allow for sampling all the channels in the channel list within one sample clock period. The greater the interchannel delay, the more time your amplifier is given to settle before the next reading (see the settling time tutorial linked below).
For example code for data acquisition, please refer to the DAQ examples that install with your NI-DAQ installation.