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National Instruments DAQ S Series User Manual

National Instruments DAQ S Series User Manual

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Summary of Contents for National Instruments DAQ S Series

  • Page 1 PXIe-6124...
  • Page 2 DAQ S Series NI 6124/6154 User Manual DAQ-STC2 S Series Simultaneous Sampling Multifunction Input/Output Devices NI 6124/6154 User Manual August 2008 372613A-01...
  • Page 3 Thailand 662 278 6777, Turkey 90 212 279 3031, United Kingdom 44 (0) 1635 523545 For further support information, refer to the Technical Support and Professional Services appendix. To comment on National Instruments documentation, refer to the National Instruments Web site at and enter ni.com/info the info code feedback ©...
  • Page 4 Instruments Corporation. National Instruments respects the intellectual property of others, and we ask our users to do the same. NI software is protected by copyright and other intellectual property laws. Where NI software may be used to reproduce software or other materials belonging to others, you may use NI software only to reproduce materials that you may reproduce in accordance with the terms of any applicable license or other legal restriction.
  • Page 5 These classes are known as Class A (for use in industrial-commercial locations only) or Class B (for use in residential or commercial locations). All National Instruments (NI) products are FCC Class A products. Depending on where it is operated, this Class A product could be subject to restrictions in the FCC rules. (In Canada, the Department of Communications (DOC), of Industry Canada, regulates wireless interference in much the same way.) Digital...

  • Page 6: Table Of Contents

    +5 V Power Source ......................3-3 Chapter 4 Analog Input Analog Input Terminal Configuration ................4-2 Input Polarity and Range ....................4-3 Working Voltage Range ....................4-4 AI Data Acquisition Methods ..................4-4 Analog Input Triggering ....................4-6 © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 7 Contents Connecting Analog Input Signals.................. 4-6 Types of Signal Sources.................. 4-7 Differential Connections for Ground-Referenced Signal Sources....4-7 Common-Mode Signal Rejection Considerations ......4-9 Differential Connections for Non-Referenced or Floating Signal Sources ..4-9 DC-Coupled..................4-10 AC-Coupled..................4-11 Field Wiring Considerations ................4-11 Minimizing Drift in Differential Mode ............
  • Page 8 Counter Input Applications....................7-2 Counting Edges ....................7-2 Single Point (On-Demand) Edge Counting ........7-2 Buffered (Sample Clock) Edge Counting .........7-3 Controlling the Direction of Counting ..........7-4 Pulse-Width Measurement ................7-4 Single Pulse-Width Measurement.............7-4 Buffered Pulse-Width Measurement..........7-5 © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 9 Contents Period Measurement ..................7-6 Single Period Measurement.............. 7-6 Buffered Period Measurement............7-7 Semi-Period Measurement ................7-7 Single Semi-Period Measurement ............ 7-8 Buffered Semi-Period Measurement ..........7-8 Frequency Measurement ................. 7-9 Choosing a Method for Measuring Frequency ......... 7-12 Position Measurement..................7-14 Measurements Using Quadrature Encoders........
  • Page 10 Chapter 9 Digital Routing and Clock Generation Clock Routing ........................9-1 80 MHz Timebase ...................9-2 20 MHz Timebase ...................9-2 100 kHz Timebase...................9-2 External Reference Clock................9-2 10 MHz Reference Clock ................9-3 Synchronizing Multiple Devices ...................9-3 © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 11 Contents Real-Time System Integration (RTSI) ................9-4 RTSI Connector Pinout ................... 9-4 Using RTSI as Outputs ................... 9-5 Using RTSI Terminals as Timing Input Signals..........9-6 RTSI Filters..................... 9-6 PXI Clock and Trigger Signals..................9-8 PXI_CLK10 ....................9-8 PXI Triggers....................9-8 PXI_STAR Trigger ..................

  • Page 12: About This Manual

    About This Manual The NI 6124/6154 User Manual contains information about using the National Instruments S Series NI 6124 and NI 6154 data acquisition (DAQ) devices with NI-DAQmx 8.8 and later. Conventions The following conventions appear in this manual: <>...

  • Page 13: Related Documentation

    Start»All Programs»National Instruments»NI-DAQ»DAQ Getting Started Guide. The NI-DAQ Readme lists which devices are supported by this version of NI-DAQmx. Select Start»All Programs»National Instruments» NI-DAQ»NI-DAQ Readme. The NI-DAQmx Help contains general information about measurement concepts, key NI-DAQmx concepts, and common applications that are applicable to all programming environments.

  • Page 14: Measurement Studio

    Measurement Studio, refer to the NI Measurement Studio Help, which is fully integrated with the Microsoft Visual Studio .NET help. To view this help file in Visual Studio. NET, select Measurement Studio» NI Measurement Studio Help. © National Instruments Corporation xiii NI 6124/6154 User Manual...

  • Page 15: Ansi C Without Ni Application Software

    Select Start»All Programs»National Instruments»NI-DAQ»NI-DAQmx Help. The NI-DAQmx C Reference Help describes the NI-DAQmx Library functions, which you can use with National Instruments data acquisition devices to develop instrumentation, acquisition, and control applications. Select Start»All Programs»National Instruments»NI-DAQ» NI-DAQmx C Reference Help.

  • Page 16: Device Documentation And Specifications

    PDFs. Refer to the Adobe Systems Incorporated Web site at to download Acrobat Reader. Refer to the www.adobe.com National Instruments Product Manuals Library at ni.com/manuals updated documentation resources. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 17: Getting Started

    Installing Other Software If you are using other software, refer to the installation instructions that accompany your software. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 18: Installing The Hardware

    Chapter 1 Getting Started Installing the Hardware The DAQ Getting Started Guide contains non-software-specific information about how to install PCI and PXI Express devices, as well as accessories and cables. Device Self-Calibration NI recommends that you self-calibrate your S Series device after installation and whenever the ambient temperature changes.

  • Page 19: Device Pinouts

    Refer to the specifications for your device, the NI 6124 Specifications or the NI 6154 Specifications, available on the NI-DAQ Device Document Browser or , for more detailed information about the ni.com/manuals NI 6124 and NI 6154 devices. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 20: Daq System Overview

    Information, for a list of devices and their compatible accessories. – 1 Sensors and Transducers 4 DAQ Hardware 2 Signal Conditioning 5 Personal Computer/Chassis 3 Cable Assembly and DAQ Software Figure 2-1. Typical DAQ System © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 21: Daq Hardware

    Chapter 2 DAQ System Overview DAQ Hardware DAQ hardware digitizes signals, performs D/A conversions to generate analog output signals, and measures and controls digital I/O signals. The following sections contain more information about specific components of the DAQ hardware. Figure 2-2 shows the components of the non-isolated S Series (NI 6124) device.

  • Page 22: Daq-Stc2

    • Many triggering modes • Independent AI, AO, DI, and DO FIFOs • Generation and routing of RTSI signals for multi-device synchronization • Generation and routing of internal and external timing signals © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 23: Calibration Circuitry

    Chapter 2 DAQ System Overview • Two flexible 32-bit counter/timer modules with hardware gating • Digital waveform acquisition and generation • Static DIO signals • True 5 V high current drive DO • PLL for clock synchronization • PCI/PXI interface •...

  • Page 24: External Calibration

    The accuracy specifications of your device change depending on how long it has been since your last external calibration. National Instruments recommends that you calibrate your device at least as often as the intervals listed in the accuracy specifications.

  • Page 25: Programming Devices In Software

    NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. Programming Devices in Software National Instruments measurement devices are packaged with NI-DAQmx driver software, an extensive library of functions and VIs you can call from your application software, such as LabVIEW or LabWindows/CVI, to program all the features of your NI measurement devices.

  • Page 26: I/O Connector

    Analog Output Ground—The AO voltages and the external reference voltage are referenced to these pins. D GND — — Digital Ground—These pins supply the reference for the digital signals at the I/O connector and the +5 VDC supply. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 27: Ni 6154 I/O Connector Signal Descriptions

    Chapter 3 I/O Connector Table 3-1. NI 6124 Device Signal Descriptions (Continued) I/O Connector Pin Reference Direction Signal Description P0.<0..7> D GND Input or Output Digital I/O Channels 0 through 7—You can individually configure each signal as an input or output. P0.6 and P0.7 can also control the up/down signal of Counters 0 and 1, respectively.

  • Page 28: +5 V Power Source

    Never connect these +5 V power pins to analog or digital ground or to any other voltage source on the S Series device or any other device. Doing so can damage the device and the computer. NI is not liable for damage resulting from such a connection. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 29: Analog Input

    Figure 4-2 shows the analog input circuitry of each channel of the isolated S Series (NI 6154) device. Isolation Instrumentation Barrier Amplifier Filter AI Data AI FIFO Digital AI– Isolators AI Timing Signals Figure 4-2. Isolated S Series Analog Input Block Diagram © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 30: Analog Input Terminal Configuration

    Chapter 4 Analog Input On S Series devices, each channel uses its own instrumentation amplifier, FIFO, multiplexer (mux), and A/D converter (ADC) to achieve simultaneous data acquisition. The main blocks featured in the S Series analog input circuitry are as follows: •...

  • Page 31: Input Polarity And Range

    For more information about programming these settings, refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 32: Working Voltage Range

    Chapter 4 Analog Input Working Voltage Range On most S Series devices, the PGIA operates normally by amplifying signals of interest while rejecting common-mode signals under the following three conditions: • The common-mode voltage (V ), which is equivalent to subtracting AI <0..x>...
  • Page 33 Non-Buffered—In non-buffered acquisitions, data is read directly from the FIFO on the device. Typically, hardware-timed non-buffered operations are used to read single samples with known time increments between them and small latency. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 34: Analog Input Triggering

    Chapter 4 Analog Input Analog Input Triggering Analog input supports two different triggering actions: start and reference. An analog or digital hardware trigger can initiate these actions. All S Series devices support digital triggering, and some also support analog triggering. To find your device’s triggering options, refer to the specifications document for your device.

  • Page 35: Types Of Signal Sources

    Differential Connections for Ground-Referenced Signal Sources Figure 4-6 shows how to connect a ground-referenced signal source to a channel on a non-isolated S Series device. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 36 Chapter 4 Analog Input Non-Isolated S Series Device Instrumentation AI 0+ Amplifier Ground- Referenced Signal Source – AI 0– Measured – Voltage Common- – Mode Noise and Ground Potential – AI 0 GND I/O Connector AI 0 Connections Shown Figure 4-3. Differential Connection for Ground-Referenced Signals on Non-Isolated Devices Figure 4-4 shows how to connect a ground-referenced signal source to a channel on an isolated S Series device.

  • Page 37: Common-Mode Signal Rejection Considerations

    – AI 0– Measured – Voltage Bias – Current Return Paths Bias AI 0 GND Resistor I/O Connector AI 0 Connections Shown Figure 4-5. Differential Connection for Non-Referenced Signals on Non-Isolated Devices © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 38: Dc-Coupled

    Chapter 4 Analog Input Figure 4-5 shows a bias resistor connected between AI 0 – and the floating signal source ground. This resistor provides a return path for the bias current. A value of 10 kΩ to 100 kΩ is usually sufficient. If you do not use the resistor and the source is truly floating, the source is not likely to remain within the common-mode signal range of the instrumentation amplifier, so the instrumentation amplifier saturates, causing erroneous readings.

  • Page 39: Ac-Coupled

    S Series device if you do not take proper care when running signal wires between signal sources and the device. The following recommendations apply mainly to AI signal routing, although they also apply to signal routing in general. © National Instruments Corporation 4-11 NI 6124/6154 User Manual...

  • Page 40: Minimizing Drift In Differential Mode

    Chapter 4 Analog Input Minimize noise pickup and maximize measurement accuracy by taking the following precautions. • Use differential AI connections to reject common-mode noise. • Use individually shielded, twisted-pair wires to connect AI signals to the device. With this type of wire, the signals attached to the AI + and AI –...

  • Page 41: Analog Input Timing Signals

    AI Start Trigger Don't Care AI Reference Trigger AI Sample Clock Sample Counter Figure 4-8. Typical Pretriggered DAQ Sequence © National Instruments Corporation 4-13 NI 6124/6154 User Manual...

  • Page 42: Ai Sample Clock Signal

    Chapter 4 Analog Input If an AI Reference Trigger (ai/ReferenceTrigger) pulse occurs before the specified number of pretrigger samples are acquired, the trigger pulse is ignored. Otherwise, when the AI Reference Trigger pulse occurs, the sample counter value decrements until the specified number of posttrigger samples have been acquired.

  • Page 43: Using An External Source

    AI Sample Clock, you also can specify a configurable delay from AI Start Trigger to the first AI Sample Clock pulse. By default, this delay is set to two ticks of the AI Sample Clock Timebase signal. © National Instruments Corporation 4-15 NI 6124/6154 User Manual...

  • Page 44: Ai Sample Clock Timebase Signal

    Chapter 4 Analog Input Figure 4-9 shows the relationship of AI Sample Clock to AI Start Trigger. AI Sample Clock Timebase AI Start Trigger AI Sample Clock Delay From Start Trigger Figure 4-9. AI Sample Clock and AI Start Trigger AI Sample Clock Timebase Signal You can route any of the following signals to be the AI Sample Clock Timebase (ai/SampleClockTimebase) signal:...

  • Page 45: Using An Internal Source

    Use one of the following signals as the source of AI Convert Clock Timebase: • AI Sample Clock Timebase • 20 MHz Timebase AI Convert Clock Timebase is not available as an output on the I/O connector. © National Instruments Corporation 4-17 NI 6124/6154 User Manual...

  • Page 46: Ai Hold Complete Event Signal

    Chapter 4 Analog Input AI Hold Complete Event Signal The AI Hold Complete Event (ai/HoldCompleteEvent) signal generates a pulse after each A/D conversion begins. You can route ai/HoldCompleteEvent out to any PFI <0..15> or RTSI <0..7> terminal. The polarity of ai/HoldCompleteEvent is software-selectable, but is typically configured so that a low-to-high leading edge can clock external AI multiplexers indicating when the input signal has been sampled and can be removed.

  • Page 47: Using An Analog Source

    (with some limitations) before the DAQ device discards it. Refer to the KnowledgeBase document, Can a Pretriggered Acquisition be Continuous?, for more information. To access this KnowledgeBase, go to and enter the info code ni.com/info rdcanq © National Instruments Corporation 4-19 NI 6124/6154 User Manual...

  • Page 48: Using A Digital Source

    Chapter 4 Analog Input When the reference trigger occurs, the DAQ device continues to write samples to the buffer until the buffer contains the number of posttrigger samples desired. Figure 4-10 shows the final buffer. Reference Trigger Pretrigger Samples Complete Buffer Figure 4-10.

  • Page 49: Getting Started With Ai Applications In Software

    Note For more information about programming analog input applications and triggers in software, refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation 4-21 NI 6124/6154 User Manual...

  • Page 50: Analog Output

    Figure 5-2 shows the analog output circuitry of an isolated S Series (NI 6154) device. Isolation Barrier DAC0 AO Data AO FIFO Digital Isolators AO Sample Clock Figure 5-2. Isolated S Series Device Analog Output Block Diagram © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 51: Minimizing Glitches On The Output Signal

    Chapter 5 Analog Output The main blocks featured in the S Series analog output circuitry are as follows: • AO FIFO—The AO FIFO enables analog output waveform generation. It is a first-in-first-out (FIFO) memory buffer between the computer and the DACs that allows you to download all the points of a waveform to your board without host computer interaction.
  • Page 52 Standard regeneration is when data from the PC buffer is continually downloaded to the FIFO to be written out. New data can be written to the PC buffer at any time without disrupting the output. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 53: Analog Output Triggering

    Chapter 5 Analog Output With FIFO regeneration, the entire buffer is downloaded to the FIFO and regenerated from there. After the data is downloaded, new data cannot be written to the FIFO. To use FIFO regeneration, the entire buffer must fit within the FIFO size. The advantage of using FIFO regeneration is that it does not require communication with the main host memory after the operation is started, thereby preventing any problems that may occur due to excessive bus...
  • Page 54 Figure 5-4 shows how AO 0 is wired on an isolated S Series device. Isolation Barrier Digital Load Analog Output Channel VOUT Isolators – AO– Isolated S Series Device Figure 5-4. Analog Output Connections for Isolated S Series Devices © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 55: Waveform Generation Timing Signals

    Chapter 5 Analog Output Waveform Generation Timing Signals There is one AO Sample Clock that causes all AO channels to update simultaneously. Figure 5-5 summarizes the timing and routing options provided by the analog output timing engine. Ctr1InternalOutput PFI 0–9, RTSI 7 Master PFI 0–9,...

  • Page 56: Using An External Source

    AO Sample Clock in NI-DAQmx, you can also specify a configurable delay from the AO Start Trigger to the first AO Sample Clock pulse. By default, this delay is two ticks of the AO Sample Clock Timebase signal. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 57: Ao Sample Clock Timebase Signal

    Chapter 5 Analog Output Figure 5-7 shows the relationship of the AO Sample Clock signal to the AO Start Trigger signal. AO Sample Clock Timebase AO Start Trigger AO Sample Clock Delay From Start Trigger Figure 5-7. AO Sample Clock and AO Start Trigger AO Sample Clock Timebase Signal You can select any PFI or RTSI pin as well as many other internal signals as the AO Sample Clock Timebase (ao/SampleClockTimebase) signal.

  • Page 58: Ao Start Trigger Signal

    DAQ device. Refer to Device Routing in MAX in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later for more information. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 59: Using An Analog Source

    Chapter 5 Analog Output Figure 5-9 shows the timing requirements of the AO Start Trigger digital source. Rising-Edge Polarity Falling-Edge Polarity = 10 ns minimum Figure 5-9. AO Start Trigger Timing Requirements Using an Analog Source When you use an analog trigger source, the waveform generation begins on the first rising edge of the Analog Comparison Event signal.

  • Page 60: Using A Digital Source

    Note For more information about programming analog output applications and triggers in software, refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation 5-11 NI 6124/6154 User Manual...

  • Page 61: Digital I/O

    Eight lines of DIO • Direction and function of each terminal individually controllable • Static digital input and output • High-speed digital waveform generation • High-speed digital waveform acquisition • DI change detection trigger/interrupt © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 62: Static Dio For Non-Isolated Devices

    Chapter 6 Digital I/O Figure 6-1 shows the circuitry of one DIO line. Each DIO line is similar. The following sections provide information about the various parts of the DIO circuit. DO Waveform Generation FIFO DO Sample Clock Static DO Buffer I/O Protection P0.

  • Page 63: Digital Waveform Triggering For Non-Isolated Devices

    DMA controller dedicated to moving data from the DI waveform acquisition FIFO to system memory. The DAQ device samples the DIO lines on each rising or falling edge of a clock signal, DI Sample Clock. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 64: Di Sample Clock Signal

    Chapter 6 Digital I/O You can configure each DIO line to be an output, a static input, or a digital waveform acquisition input. DI Sample Clock Signal (NI 6124 Only) Use the DI Sample Clock (di/SampleClock) signal to sample the P0.<0..7> terminals and store the result in the DI waveform acquisition FIFO.

  • Page 65: Digital Waveform Generation For Non-Isolated Devices

    DO Sample Clock or use an external signal as the source of the clock. If the DAQ device receives a DO Sample Clock when the FIFO is empty, the DAQ device reports an underflow error to the host software. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 66 Chapter 6 Digital I/O Using an Internal Source To use DO Sample Clock with an internal source, specify the signal source and the polarity of the signal. The source can be any of the following signals: • AI Sample Clock (ai/SampleClock) •...

  • Page 67: I/O Protection For Non-Isolated Devices

    When using your S Series device to control an SCXI chassis, DIO lines 0, 1, 2, and 4 are used as communication lines and must be left to power-up in the default high-impedance state to avoid potential damage to these signals. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 68: Di Change Detection For Non-Isolated Devices

    Chapter 6 Digital I/O DI Change Detection for Non-Isolated Devices (NI 6124 Only) You can configure the DAQ device to detect changes in the DIO signals. Figure 6-3 shows a block diagram of the DIO change detection circuitry. Enable P0.0 Synch Enable Change Detection Event...

  • Page 69: Di Change Detection Applications For Non-Isolated Devices

    TTL signals and sensing external device states, such as the state of the switch shown in the figure. Digital output applications include sending TTL signals and driving external devices, such as the LED shown in the figure. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 70: Getting Started With Dio Applications In Software On Non-Isolated Devices

    Chapter 6 Digital I/O +5 V PFI <4..7>/ P1.<4..7> PFI <0..3>/ TTL Signal P1.<0..3> +5 V Switch D GND I/O Connector Non-Isolated S Series Device Figure 6-4. Digital I/O Connections Caution Exceeding the maximum input voltage ratings, which are listed in the specifications document for each non-isolated DAQ-STC2 S Series device, can damage the DAQ device and the computer.

  • Page 71: Digital I/O For Isolated Devices

    0. You can select the up/down control input of general-purpose counters 0 and 1 from any of the six digital input lines. © National Instruments Corporation 6-11 NI 6124/6154 User Manual...

  • Page 72: I/O Protection For Isolated Devices

    Chapter 6 Digital I/O I/O Protection for Isolated Devices (NI 6154 Only) Each DIO and PFI signal is protected against over-voltage, under-voltage, and over-current conditions as well as ESD events. However, you should avoid these fault conditions by following these guidelines: •...

  • Page 73: Getting Started With Dio Applications In Software On Isolated Devices

    • Static digital output Note For more information about programming digital I/O applications and triggers in software, refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation 6-13 NI 6124/6154 User Manual...
  • Page 74 Counter 1 HW Arm Counter 1 A Counter 0 TC Counter 1 B (Counter 1 Up_Down) Counter 1 Z Input Selection Muxes Frequency Generator Frequency Output Timebase Freq Out Figure 7-1. S Series Counters © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 75: Counter Input Applications

    Chapter 7 Counters The counters have seven input signals, although in most applications only a few inputs are used. For information about connecting counter signals, refer to the Default Counter/Timer Pinouts section. Counter Input Applications Counting Edges In edge counting applications, the counter counts edges on its Source after the counter is armed.

  • Page 76: Buffered (Sample Clock) Edge Counting

    Gate. Counter Armed Sample Clock (Sample on Rising Edge) SOURCE Counter Value Buffer Figure 7-4. Buffered (Sample Clock) Edge Counting © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 77: Controlling The Direction Of Counting

    Chapter 7 Counters Controlling the Direction of Counting In edge counting applications, the counter can count up or down. You can configure the counter to do the following: • Always count up • Always count down • Count up when the Counter n B input is high; count down when it is For information about connecting counter signals, refer to the Default Counter/Timer Pinouts...

  • Page 78: Buffered Pulse-Width Measurement

    Note that if you are using an external signal as the Source, at least one Source pulse should occur between each active edge of the Gate signal. This condition ensures that correct values are returned by the counter. If this © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 79: Period Measurement

    Chapter 7 Counters condition is not met, consider using duplicate count prevention, described in the Duplicate Count Prevention section. For information about connecting counter signals, refer to the Default Counter/Timer Pinouts section. Period Measurement In period measurements, the counter measures a period on its Gate input signal after the counter is armed.

  • Page 80: Buffered Period Measurement

    In semi-period measurements, the counter measures a semi-period on its Gate input signal after the counter is armed. A semi-period is the time between any two consecutive edges on the Gate input. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 81: Single Semi-Period Measurement

    Chapter 7 Counters You can route an internal or external periodic clock signal (with a known period) to the Source input of the counter. The counter counts the number of rising (or falling) edges occurring on the Source input between two edges of the Gate signal.

  • Page 82: Frequency Measurement

    (Ft) to the Source of the counter. The known timebase can be 80MHzTimebase. For signals that might be slower than 0.02 Hz, use a slower known timebase. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 83 Chapter 7 Counters You can configure the counter to make K + 1 buffered period measurements. Recall that the first period measurement in the buffer should be discarded. Average the remaining K period measurements to determine the average period of F1. The frequency of F1 is the inverse of the average period.
  • Page 84 You then measure the long pulse with a known timebase. The S Series device can measure this long pulse more accurately than the faster input signal. © National Instruments Corporation 7-11 NI 6124/6154 User Manual...

  • Page 85: Choosing A Method For Measuring Frequency

    Chapter 7 Counters You can route the signal to measure to the Source input of Counter 0, as shown in Figure 7-13. Assume this signal to measure has frequency F1. Configure Counter 0 to generate a single pulse that is the width of N periods of the source input signal.
  • Page 86 An advantage of Method 2 is that the measurement completes in a known amount of time. • Method 3 measures high and low frequency signals accurately. However, it requires two counters. © National Instruments Corporation 7-13 NI 6124/6154 User Manual...

  • Page 87: Position Measurement

    Chapter 7 Counters Table 7-2 summarizes some of the differences in methods of measuring frequency. Table 7-2. Frequency Measurement Method Comparison Measures High Measures Low Number of Number of Frequency Frequency Counters Measurements Signals Signals Method Used Returned Accurately Accurately Poor Good Many...
  • Page 88 You can program this reload to occur in any one of the four phases in a quadrature cycle. © National Instruments Corporation 7-15 NI 6124/6154 User Manual...

  • Page 89: Measurements Using Two Pulse Encoders

    Chapter 7 Counters Channel Z behavior—when it goes high and how long it stays high—differs with quadrature encoder designs. You must refer to the documentation for your quadrature encoder to obtain timing of channel Z with respect to channels A and B. You must then ensure that channel Z is high during at least a portion of the phase you specify for reload.

  • Page 90: Buffered (Sample Clock) Position Measurement

    Source. The counter ignores additional edges on the Aux input. The counter stops counting upon receiving an active edge on the Gate input. The counter stores the count in a hardware save register. © National Instruments Corporation 7-17 NI 6124/6154 User Manual...

  • Page 91: Single Two-Signal Edge-Separation Measurement

    Chapter 7 Counters You can configure the rising or falling edge of the Aux input to be the active edge. You can configure the rising or falling edge of the Gate input to be the active edge. Use this type of measurement to count events or measure the time that occurs between edges on two signals.

  • Page 92: Counter Output Applications

    You can specify a pulse width. The pulse width is also measured in terms of a number of active edges of the Source input. You also can specify the active edge of the Source input (rising or falling). © National Instruments Corporation 7-19 NI 6124/6154 User Manual...

  • Page 93: Single Pulse Generation With Start Trigger

    Chapter 7 Counters Figure 7-22 shows a generation of a pulse with a pulse delay of four and a pulse width of three (using the rising edge of Source). Counter Armed SOURCE Figure 7-22. Single Pulse Generation Single Pulse Generation with Start Trigger The counter can output a single pulse in response to one pulse on a hardware Start Trigger signal.

  • Page 94: Pulse Train Generation

    The counter can begin the pulse train generation as soon as the counter is armed, or in response to a hardware Start Trigger. You can route the Start Trigger to the Gate input of the counter. © National Instruments Corporation 7-21 NI 6124/6154 User Manual...

  • Page 95: Finite Pulse Train Generation

    Chapter 7 Counters You also can use the Gate input of the counter as a Pause Trigger (if it is not used as a Start Trigger). The counter pauses pulse generation when the Pause Trigger is active. Figure 7-25 shows a continuous pulse train generation (using the rising edge of Source).

  • Page 96: Frequency Generation

    Figure 7-28 shows the output waveform of the frequency generator when the divider is set to 5. Frequency Output Timebase FREQ OUT (Divisor = 5) Figure 7-28. Frequency Generator Output Waveform © National Instruments Corporation 7-23 NI 6124/6154 User Manual...

  • Page 97: Frequency Division

    Chapter 7 Counters Frequency Output can be routed out to any PFI <0..15> or RTSI <0..7> terminal. All PFI terminals are set to high-impedance at startup. The FREQ OUT signal also can be routed to DO Sample Clock and DI Sample Clock. In software, program the frequency generator as you would program one of the counters for pulse train generation.

  • Page 98: Counter Timing Signals

    In this section, n refers to either Counter 0 or 1. For example, Counter n Source refers to two signals—Counter 0 Source (the source input to Counter 0) and Counter 1 Source (the source input to Counter 1). © National Instruments Corporation 7-25 NI 6124/6154 User Manual...

  • Page 99: Counter N Source Signal

    Chapter 7 Counters Counter n Source Signal The selected edge of the Counter n Source signal increments and decrements the counter value depending on the application the counter is performing. Table 7-3 lists how this terminal is used in various applications.

  • Page 100: Routing Counter N Source To An Output Terminal

    Routing Counter n Gate to an Output Terminal You can route Counter n Gate out to any PFI <0..15> or RTSI <0..7> terminal. All PFIs are set to high-impedance at startup. © National Instruments Corporation 7-27 NI 6124/6154 User Manual...

  • Page 101: Counter N Aux Signal

    Chapter 7 Counters Counter n Aux Signal The Counter n Aux signal indicates the first edge in a two-signal edge-separation measurement. Routing a Signal to Counter n Aux Each counter has independent input selectors for the Counter n Aux signal. Any of the following signals can be routed to the Counter n Aux input: •...

  • Page 102: Counter N Up_Down Signal

    The Counter n Internal Output signal changes in response to Counter n TC. The two software-selectable output options are pulse output on TC and toggle output on TC. The output polarity is software-selectable for both options. © National Instruments Corporation 7-29 NI 6124/6154 User Manual...

  • Page 103: Routing Counter N Internal Output To An Output Terminal

    Chapter 7 Counters With pulse or pulse train generation tasks, the counter drives the pulse(s) on the Counter n Internal Output signal. The Counter n Internal Output signal can be internally routed to be a counter/timer input or an “external” source for AI, AO, DI, or DO timing signals.

  • Page 104: Counter Triggering

    When using a pause trigger, the pause trigger source is routed to the Counter n Gate signal input of the counter. © National Instruments Corporation 7-31 NI 6124/6154 User Manual...

  • Page 105: Other Counter Features

    Chapter 7 Counters Other Counter Features Cascading Counters You can internally route the Counter n Internal Output and Counter n TC signals of each counter to the Gate inputs of the other counter. By cascading two counters together, you can effectively create a 64-bit counter. By cascading counters, you also can enable other applications.

  • Page 106: Prescaling

    Thus, the prescaler acts as a frequency divider on the Source and puts out a frequency that is one-eighth (or one-half) of what it is accepting. © National Instruments Corporation 7-33 NI 6124/6154 User Manual...

  • Page 107: Duplicate Count Prevention

    Chapter 7 Counters External Signal Prescaler Rollover (Used as Source by Counter) Counter Value Figure 7-31. Prescaling Prescaling is intended to be used for frequency measurement where the measurement is made on a continuous, repetitive signal. The prescaling counter cannot be read; therefore, you cannot determine how many edges have occurred since the previous rollover.

  • Page 108: Example Application That Works Correctly (No Duplicate Counting)

    Source edge after the rising edge of Gate. The details of when exactly the counter synchronizes the Gate signal vary depending on the synchronization mode. Synchronization modes are described in the section. Synchronization Modes © National Instruments Corporation 7-35 NI 6124/6154 User Manual...

  • Page 109: Example Application That Works Incorrectly (Duplicate Counting)

    Chapter 7 Counters Example Application That Works Incorrectly (Duplicate Counting) In Figure 7-33, after the first rising edge of Gate, no Source pulses occur, so the counter does not write the correct data to the buffer. No Source edge, so no value written to buffer.

  • Page 110: When To Use Duplicate Count Prevention

    Source signal. So S Series devices synchronize these signals before presenting them to the internal counter. S Series devices use one of three synchronization methods: • 80 MHz source mode • Other internal source mode • External source mode © National Instruments Corporation 7-37 NI 6124/6154 User Manual...

  • Page 111: 80 Mhz Source Mode

    Chapter 7 Counters In DAQmx, the device uses 80 MHz source mode if you perform the following: • Perform a position measurement • Select duplicate count prevention Otherwise, the mode depends on the signal that drives Counter n Source. Table 7-5 describes the conditions for each mode. Table 7-5.

  • Page 112: Other Internal Source Mode

    Source signal, and counts on the following rising edge of the source, as shown in Figure 7-37. Source Synchronize Delayed Source Count Figure 7-37. External Source Mode © National Instruments Corporation 7-39 NI 6124/6154 User Manual...

  • Page 113: Programmable Function Interfaces (Pfi)

    A static digital input • A static digital output • A timing input signal for AI, AO, DI, DO, or counter/timer functions • A timing output signal from AI, AO, DI, DO, or counter/timer functions © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 114: Pfi For Isolated Devices

    Chapter 8 Programmable Function Interfaces (PFI) Each PFI input also has a programmable debouncing filter. Figure 8-1 shows the circuitry of one PFI line. Each PFI line is similar. Timing Signals Static DO Buffer PFI x /P1 or I/O Protection PFI x /P2 Direction Control Static DI...
  • Page 115 (where x is an integer from 0 to 9). When a terminal is used as a static digital input or output, it is called P0.x or P1.x. The voltage input and output levels and the current drive levels of the PFI signals are listed in the NI 6154 Specifications. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 116: Using Pfi Terminals As Timing Input Signals

    Chapter 8 Programmable Function Interfaces (PFI) Using PFI Terminals as Timing Input Signals Use PFI terminals to route external timing signals to many different S Series functions. Each PFI terminal (or input PFI terminal) can be routed to any of the following signals: •...

  • Page 117: Using Pfi Terminals As Static Digital Inputs And Outputs

    NI 6154 Devices— When a terminal is used as a static digital input or output, it is called P0.x or P1.x. On the I/O connector, each terminal is labeled PFI x/P0.x or PFI x/P1.x. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 118: Connecting Pfi Input Signals

    Chapter 8 Programmable Function Interfaces (PFI) Connecting PFI Input Signals All PFI input connections are referenced to D GND. Figure 8-4 shows this reference, and how to connect an external PFI 0 source and an external PFI 2 source to two PFI terminals. PFI 0 PFI 2 PFI 0...
  • Page 119 Refer to the KnowledgeBase document, Digital Filtering with M Series and CompactDAQ, for more information about digital filters and counters. To access this KnowledgeBase, go to and enter the info ni.com/info code rddfms © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 120: I/O Protection

    Chapter 8 Programmable Function Interfaces (PFI) I/O Protection Each DIO and PFI signal is protected against overvoltage, undervoltage, and overcurrent conditions as well as ESD events. However, you should avoid these fault conditions by following these guidelines: • If you configure a PFI or DIO line as an output, do not connect it to any external signal source, ground, or power supply.
  • Page 121 1 or 0. Refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later for more information about setting power-up states in NI-DAQmx or MAX. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 122: Digital Routing And Clock Generation

    ÷ 8 80 MHz Output Selectors) Oscillator External 80 MHz Timebase Reference RTSI <0..7> Clock PXI_CLK10 20 MHz Timebase ÷ PXI_STAR 100 kHz Timebase ÷ Figure 9-1. S Series Clock Routing Circuitry © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 123: 80 Mhz Timebase

    Chapter 9 Digital Routing and Clock Generation 80 MHz Timebase The 80 MHz Timebase can be used as the Source input to the 32-bit general-purpose counter/timers. The 80 MHz Timebase is generated from the following sources: • Onboard oscillator • External signal (by using the external reference clock) 20 MHz Timebase The 20 MHz Timebase normally generates many of the AI and AO timing...

  • Page 124: 10 Mhz Reference Clock

    Once all of the devices are using or referencing a common timebase, you can synchronize operations across them by sending a common start trigger out across the RTSI bus and setting their sample clock rates to the same value. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 125: Real-Time System Integration (Rtsi)

    • Share trigger signals between devices Many National Instruments DAQ, motion, vision, and CAN devices support RTSI. In a PCI system, the RTSI bus consists of the RTSI bus interface and a ribbon cable. The bus can route timing and trigger signals between several functions on as many as five DAQ, vision, motion, or CAN devices in the computer.

  • Page 126: Using Rtsi As Outputs

    AI Reference Trigger (ai/ReferenceTrigger) • AI Convert Clock* (ai/ConvertClock) • AI Sample Clock (ai/SampleClock) • AO Sample Clock* (ao/SampleClock) • AO Start Trigger (ao/StartTrigger) • AO Pause Trigger (ao/PauseTrigger) • 10 MHz Reference Clock © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 127: Using Rtsi Terminals As Timing Input Signals

    Chapter 9 Digital Routing and Clock Generation • Counter n Source, Gate, Z, Internal Output • Change Detection Event • Analog Comparison Event • FREQ OUT • PFI <0..5> Note Signals with a * are inverted before being driven on the RTSI terminals. Using RTSI Terminals as Timing Input Signals You can use RTSI terminals to route external timing signals to many different S Series functions.
  • Page 128 When a PFI input is routed directly to RTSI, or a RTSI input is routed directly to PFI, the S Series device does not use the filtered version of the input signal. © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 129: Pxi Clock And Trigger Signals

    Chapter 9 Digital Routing and Clock Generation Refer to the KnowledgeBase document, Digital Filtering with M Series and CompactDAQ, for more information about digital filters and counters. To access this KnowledgeBase, go to and enter the info ni.com/info code rddfms PXI Clock and Trigger Signals (NI 6124 Only) PXI clock and trigger signals are only available on PXI and...

  • Page 130: Pxi_Star Filters

    Filter Setting Pass Signal) Pass Filter Not Pass Filter 125 ns 125 ns 100 ns 6.425 µs 6.425 µs 6.400 µs 2.56 ms ~101,800 2.56 ms 2.54 ms Disabled — — — © National Instruments Corporation NI 6124/6154 User Manual...

  • Page 131: Routing Signals In Software

    Chapter 9 Digital Routing and Clock Generation The filter setting for each input can be configured independently. On power up, the filters are disabled. Figure 9-4 shows an example of a low to high transition on an input that has its filter set to 125 ns (N = 5). RTSI, PFI, or Filtered input goes PXI_STAR Terminal...

  • Page 132: Bus Interface

    NI PXI Express S Series devices can be installed in any PXI Express slot or PXI hybrid slots in PXI Express chassis. PXI specifications are developed by the PXI System Alliance ( www.pxisa.org © National Instruments Corporation 10-1 NI 6124/6154 User Manual...

  • Page 133: Data Transfer Methods

    CPU. This method makes DMA the fastest available data transfer method. National Instruments uses DMA hardware and software technology to achieve high throughput rates and to increase system utilization. DMA is the default method of data transfer for DAQ devices that support it.

  • Page 134: Triggering With A Digital Source

    The edge can be either the rising edge or falling edge of the digital signal. A rising edge is a transition from a low logic level to a high logic level. A falling edge is a high to low transition. © National Instruments Corporation 11-1 NI 6124/6154 User Manual...

  • Page 135: Triggering With An Analog Source

    Chapter 11 Triggering Figure 11-1 shows a falling-edge trigger. Digital Trigger Falling edge initiates acquisition Figure 11-1. Falling-Edge Trigger You can also program your DAQ device to perform an action in response to a trigger from a digital source. The action can affect the following: •...

  • Page 136: Analog Input Channel

    Configure the analog trigger circuitry to different triggering modes: • Analog Edge Triggering—Configure the analog trigger circuitry to detect when the analog signal is below or above a level you specify. © National Instruments Corporation 11-3 NI 6124/6154 User Manual...
  • Page 137 Chapter 11 Triggering In below-level analog triggering mode, shown in Figure 11-3, the trigger is generated when the signal value is less than Level. Level Analog Comparison Event Figure 11-3. Below-Level Analog Triggering Mode In above-level analog triggering mode, shown in Figure 11-4, the trigger is generated when the signal value is greater than Level.
  • Page 138 (Level + Hysteresis) Hysteresis Low threshold (Level) Then signal must go below low threshold before Analog Comparison Event asserts Analog Comparison Event Figure 11-6. Analog Edge Triggering with Hysteresis Falling Slope Example © National Instruments Corporation 11-5 NI 6124/6154 User Manual...

  • Page 139: Analog Trigger Accuracy

    Chapter 11 Triggering Analog Window Triggering—An analog window trigger occurs • when an analog signal either passes into (enters) or passes out of (leaves) a window defined by two voltage levels. Specify the levels by setting the window Top value and the window Bottom value. Figure 11-7 demonstrates a trigger that asserts when the signal enters the window.

  • Page 140: Device-Specific Information

    The AO channels on the NI 6124 contain 16-bit DACs that are capable of 4 MS/s for one channel or 2.5 MS/s for each of two channels. Refer to the NI 6124 Specifications for more detailed information about the AO capabilities of the NI 6124. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 141 Appendix A Device-Specific Information Note The AO channels do not have analog or digital filtering hardware and do produce images in the frequency domain related to the update rate. NI 6124 I/O Connector Pinout Figure A-1 shows the pin assignments for the 68-pin connector on the NI 6124.
  • Page 142 Counter Signals in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. For a detailed description of each signal, refer to the NI 6124 I/O Connector Signal Descriptions section of Chapter 3, Connector. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 143 Appendix A Device-Specific Information NI 6124 Block Diagram Figure A-2 shows the NI 6124 block diagram. AI Data ADC(0) 16-Bit PGIA Channel Cal Relay AI Convert(0) Control(0) Control(0) 16-Bit AI Data ADC(1) PGIA Channel Board Cal Relay AI Convert(1) Control(1) Power Control(1) Spartan-3A...
  • Page 144 When using a cable shield, use separate shields for the analog and digital halves of the cable. Failure to do so results in noise coupling into the analog signals from transient digital signals. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 145 Appendix A Device-Specific Information Mating connectors and a backshell kit for making custom 68-pin cables are available from NI. NI recommends that you use one of the following connectors with the I/O connector on your device. • Honda 68-position, solder cup, female connector •...
  • Page 146 250 kS/s for each channel. The AO channels are isolated from each other, from the AI channels, and from the chassis. Refer to the NI 6154 Specifications for more detailed information about the AO capabilities of the NI 6154. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 147 Appendix A Device-Specific Information NI 6154 I/O Connector Pinout Figure A-3 shows the pin assignments for the 37-pin I/O connector on the NI 6154. AI 0– AI 0+ AI 1– AI 1+ AI 2– AI 2+ AI 3– AI 3+ AO 0–...
  • Page 148 Counter Signals in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. For a detailed description of each signal, refer to the NI 6154 I/O Connector Signal Descriptions section of Chapter 3, Connector. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 149 Appendix A Device-Specific Information NI 6154 Block Diagram Figure A-4 shows the NI 6154 block diagram. Circuit AI 0 PGIA 16-Bit FPGA AO 0 AO 0 PGIA 16-Bit AI 1 PGIA 16-Bit AO 1 AO 1 PGIA 16-Bit Analog Analog Output Input AI 2...
  • Page 150 DB37M-DB37F-EP—37-pin male-to-female enhanced performance shielded I/O cable, 1 m (EMI shielding) For more information about optional equipment available from National Instruments, refer to the National Instruments catalog or visit the National Instruments Web site at ni.com NI 6154 Isolation and Digital Isolators The NI 6154 is an isolated data acquisition device.

  • Page 151: Digital Isolation

    Appendix A Device-Specific Information The non-isolated ground is connected to the chassis ground of the PC or chassis where the device is installed. The isolated ground is not connected to the chassis ground of the PC or chassis. The isolated ground can be at a higher or lower voltage relative to the non-isolated ground.
  • Page 152 Improved safety—Isolation creates an insulation barrier so you can make floating measurements while protecting against large transient voltage spikes. NI 6154 Specifications Refer to the NI 6154 Specifications for more detailed information about the device. © National Instruments Corporation A-13 NI 6124/6154 User Manual...

  • Page 153: Technical Support And Professional Services

    Technical Support and Professional Services Visit the following sections of the award-winning National Instruments Web site at for technical support and professional services: ni.com • Support—Technical support at includes the ni.com/support following resources: – Self-Help Technical Resources—For answers and solutions,...
  • Page 154 Appendix B Technical Support and Professional Services Declaration of Conformity (DoC)—A DoC is our claim of • compliance with the Council of the European Communities using the manufacturer’s declaration of conformity. This system affords the user protection for electromagnetic compatibility (EMC) and product safety.
  • Page 155 Degree. > Greater than. < Less than. – Negative of, or minus. Ω Ohms. Per. Percent. ± Plus or minus. Positive of, or plus. Amperes—the unit of electric current. Analog-to-digital. Alternating current. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 156 Glossary Analog-to-digital converter—an electronic device, often an integrated circuit, that converts an analog voltage to a digital number. Application Development Environment—a software environment incorporating the development, debug, and analysis tools for software development. LabVIEW, Measurement Studio, and Visual Studio are examples.
  • Page 157 The manner in which a signal is connected from one circuit to another. When applied to instrument products or DAQ cards, it refers to the input signal coupling technique. Counter signal. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 158 Glossary Digital-to-analog. Digital-to-analog converter—an electronic device, often an integrated circuit, that converts a digital number into a corresponding analog voltage or current. See data acquisition (DAQ). DAQ device A device that acquires or generates data and can contain multiple channels and conversion devices.
  • Page 159 Signal sources with voltage signals that are not connected to an absolute sources reference of system ground. Also called nonreferenced signal sources. Some common examples of floating signal sources are batteries, transformers, and thermocouples. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 160 Glossary FPGA Field-programmable gate array. gain The factor by which a signal is amplified, often expressed in dB. Gain as a function of frequency is commonly referred to as the magnitude of the frequency response function. grounded signal Signal sources with voltage sources that are referenced to a system ground sources such as the earth or building ground.
  • Page 161 Noise corrupts signals you are trying to send or receive. Peripheral Component Interconnect—a high-performance expansion bus architecture originally developed by Intel to replace ISA and EISA. It offers a theoretical maximum transfer rate of 132 Mbytes/s. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 162 The time for a signal to transition from 10% to 90% of the maximum signal amplitude. Root mean square. RTSI bus Real-Time System Integration bus—the National Instruments timing bus that connects DAQ devices directly, by means of connectors on top of the devices, for precise synchronization of functions. NI 6124/6154 User Manual...
  • Page 163 Conceptually, a task represents a measurement or generation you want to perform. terminal count The highest value of a counter. Gate hold time. Gate setup time. © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 164 Glossary Gate pulse width. Total harmonic distortion—the ratio of the total rms signal due to harmonic distortion to the overall rms signal, in dB or percent. THD+N Signal-to-THD plus noise—the ratio in decibels of the overall rms signal to the rms signal of harmonic distortion, plus noise introduced. thermocouple A temperature sensor created by joining two dissimilar metals.
  • Page 165 Glossary Volts, input low. Volts in. Measured voltage. Volts, output high. Volts, output low. Volts out. Volts, root mean square. Ground-referenced signal source. virtual channel See channel. © National Instruments Corporation G-11 NI 6124/6154 User Manual...
  • Page 166 ANSI C documentation, xiv circuitry, 4-2 AO Pause Trigger signal, 5-10 data acquisition methods, 4-4 AO Sample Clock signal, 5-6 fundamentals, 4-1 AO Sample Clock Timebase signal, 5-8 overview, 4-1 AO Start Trigger signal, 5-9 © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 167 Index applications PXI, and trigger signals, 9-8 counter input, 7-2 routing, 9-1 counter output, 7-19 common-mode edge counting, 7-2 input range, 4-3 arm start trigger, 7-31 noise differential ground-referenced signals, 4-9 differential non-referenced or block diagram floating signals, 4-11 NI 6124, A-4 differential signals, 4-9 NI 6154, A-10 rejection, 4-11...
  • Page 168 7-20 differential connections synchronization modes, 7-37 for ground-referenced signal sources, 4-7, timing signals, 7-25 4-11 triggering, 7-31 for non-referenced or floating signal counting edges, 7-2 sources, 4-9 digital isolation (NI 6154), A-12 © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 169 Index example, 7-35 triggering, 11-1 waveform acquisition, 6-3 prevention example, 7-36 waveform generation, 6-5 digital I/O, 6-1 block diagram, 6-2 edge counting, 7-2 circuitry, 6-2 buffered, 7-3 connecting signals, 6-9 on-demand, 7-2 DI change detection, 6-8 sample clock, 7-3 digital waveform generation, 6-5 single point, 7-2 getting started with applications in edge-separation measurement...
  • Page 170 I/O connector choosing frequency, 7-12 NI 6124, A-2 frequency, 7-9 NI 6154, A-8 period, 7-6 signal descriptions position, 7-14 isolated devices, 3-2 pulse-width, 7-4 non-isolated devices, 3-1 semi-period, 7-7 single period, 7-6 © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 171 7-31 mux, 4-2 period measurement, 7-6 buffered, 7-7 single, 7-6 PFI, 8-1, 8-2 National Instruments support and services, B-1 connecting input signals, 8-6 .NET languages documentation, xiv exporting timing output signals using PFI terminals, 8-4 NI 6124, A-4...
  • Page 172 S Series isolated devices (NI 6154), 3-2 S Series non-isolated devices (NI 6124), 3-1 real-time system integration bus, 9-4 reciprocal frequency measurement, 7-11 signal routing, RTSI bus, 9-4 signal sources, 4-7 © National Instruments Corporation NI 6124/6154 User Manual...
  • Page 173 Index software, 1-1 signals AI Convert Clock, 4-16 AI applications, 4-21 AI Convert Clock Timebase, 4-17 AO applications, 5-11 AI Reference Trigger, 4-19 DIO applications for isolated devices, 6-13 AI Sample Clock, 4-14 NI resources, B-1 AI Sample Clock Timebase, 4-16 programming devices, 2-6 AI Start Trigger, 4-18 routing signals in, 9-10...
  • Page 174 I/Os, 8-5 as timing input signals, 8-4 to export timing output signals, 8-4 RTSI as outputs, 9-5 terminals as timing input signals, 9-6 using PFI terminals as static digital I/Os, 8-5 © National Instruments Corporation NI 6124/6154 User Manual...

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