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National Instruments Network Device DAQ S User Manual

National Instruments Network Device DAQ S User Manual

National instruments network device user's manual
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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

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Summary of Contents for National Instruments Network Device DAQ S

  • Page 1 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 2 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 3: Important Information

    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 4 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 5: 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 6 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 7 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 Contents NI 6124/6154 User Manual...
  • Page 8 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 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 Contents NI 6124/6154 User Manual...
  • Page 10 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 11: 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 12: 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 13: Measurement Studio

    Microsoft Visual Studio .NET help. To view this help file in Visual Studio. NET, select Measurement Studio» NI Measurement Studio Help. © National Instruments Corporation VI and Function Reference»Measurement I/O VIs and Functions—Describes the LabVIEW NI-DAQmx VIs and properties.

  • Page 14: 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 15: Device Documentation And Specifications

    Adobe Acrobat Reader with Search and Accessibility 5.0.5 or later installed to view the PDFs. Refer to the Adobe Systems Incorporated Web site at National Instruments Product Manuals Library at updated documentation resources. © National Instruments Corporation ni.com/training ni.com/support...

  • Page 16: Getting Started

    Installing Other Software If you are using other software, refer to the installation instructions that accompany your software. © National Instruments Corporation , offers NI-DAQmx users step-by-step instructions for installing ni.com/manuals ni.com/ NI 6124/6154 User Manual...

  • Page 17: 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 18: 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 NI 6124 and NI 6154 devices. © National Instruments Corporation Device-Specific Information, for NI 6124 and , for more detailed information about the ni.com/manuals...

  • Page 19: Daq System Overview

    S Series device, and the programming software. Refer to Appendix A, compatible accessories. 1 Sensors and Transducers 2 Signal Conditioning 3 Cable Assembly © National Instruments Corporation Device-Specific Information, for a list of devices and their – 4 DAQ Hardware 5 Personal Computer/Chassis Figure 2-1.

  • Page 20: 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 21: Daq-Stc2

    S Series data acquisition hardware. Some key features of this engine include the following: • • • • • © National Instruments Corporation S Series isolated hardware also includes bank and Isolation Barrier Digital Isolators Routing Figure 2-3. General NI 6154 Block Diagram...

  • Page 22: Calibration Circuitry

    Chapter 2 DAQ System Overview • • • • • • • Calibration Circuitry Calibration is the process of making adjustments to a measurement device to reduce errors associated with measurements. Without calibration, the measurement results of your device will drift over time and temperature. Calibration adjusts for these changes to improve measurement accuracy and ensure that your product meets its required specifications.

  • Page 23: 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 24: Programming Devices In Software

    DAQ System Overview • 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. NI-DAQmx...

  • Page 25: I/O Connector

    AO <0..1> AO GND AO GND — D GND — © National Instruments Corporation NI 6124 I/O Connector Signal Descriptions NI 6154 I/O Connector Signal Descriptions Device-Specific Table 3-1 describes the signals found on the NI 6124 I/O Direction —...

  • Page 26: 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 P0.<0..7> D GND PFI <0..7>/P1.<0..7> D GND PFI <8..15>/P2.<0..7> +5 V D GND NI 6154 I/O Connector Signal Descriptions (NI 6154 Only) connector. For more information about these signals, refer to the NI 6154 Specifications.

  • Page 27: +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 Direction Signal Description...

  • Page 28: Analog Input

    AI– Figure 4-2 shows the analog input circuitry of each channel of the isolated S Series (NI 6154) device. Instrumentation Amplifier AI– © National Instruments Corporation Amplifier Filter Analog Trigger Figure 4-1. Non-Isolated S Series Analog Input Block Diagram Filter Figure 4-2.

  • Page 29: 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 30: 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 – ( – 153 μV...

  • Page 31: 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: • • • If any of these conditions are exceeded, the input voltage is clamped until the fault condition is removed.
  • Page 32 © National Instruments Corporation Hardware-timed acquisitions have several advantages over software-timed acquisitions: – The time between samples can be much shorter. – The timing between samples can be deterministic. – Hardware-timed acquisitions can use hardware triggering. For more information, refer to Chapter 11, Triggering.

  • Page 33: 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 34: 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 Analog Input Terminal Configuration Floating Signal Sources—A floating signal source is not connected in any way to the building ground system, and instead has an isolated ground-reference point.
  • Page 35 Chapter 4 Analog Input Ground- Referenced Signal Source – Common- Mode Noise and Ground Potential – I/O Connector Figure 4-4 shows how to connect a ground-referenced signal source to a channel on an isolated S Series device. Isolated S Series Device AI 0+ Ground- Referenced...

  • Page 36: Differential Connections For Non-Referenced Or Floating Signal Sources

    – Bias Current Return Paths Bias Resistor I/O Connector © National Instruments Corporation Non-Isolated S Series Device AI 0+ AI 0– AI 0 GND AI 0 Connections Shown Figure 4-5. Differential Connection for Non-Referenced Signals on Non-Isolated Devices Chapter 4...

  • Page 37: 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 38: Ac-Coupled

    The following recommendations apply mainly to AI signal routing, although they also apply to signal routing in general. © National Instruments Corporation High Source Impedance—For larger source impedances, this connection leaves the DIFF signal path significantly off balance. Noise that couples electrostatically onto the positive line does not couple onto the negative line because it is connected to ground.

  • Page 39: Minimizing Drift In Differential Mode

    Chapter 4 Analog Input Minimize noise pickup and maximize measurement accuracy by taking the following precautions. • • • • • • Refer to the NI Developer Zone document, Field Wiring and Noise Considerations for Analog Signals, for more information. Minimizing Drift in Differential Mode If the readings from the DAQ device are random and drift rapidly, you should check the ground-reference connections.

  • Page 40: Analog Input Timing Signals

    AI Start Trigger AI Reference Trigger AI Sample Clock Sample Counter © National Instruments Corporation Figure 4-7. Typical Posttriggered DAQ Sequence Don't Care Figure 4-8. Typical Pretriggered DAQ Sequence 4-13 Chapter 4...

  • Page 41: 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 42: 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 PFI <0..15> RTSI <0..7> PXI_STAR...

  • Page 43: 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 Signal You can route any of the following signals to be the AI Sample Clock Timebase (ai/SampleClockTimebase) signal: • •...

  • Page 44: Using An Internal Source

    Use one of the following signals as the source of AI Convert Clock Timebase: • • AI Convert Clock Timebase is not available as an output on the I/O connector. © National Instruments Corporation AI Convert Clock Timebase (divided down) Counter n Internal Output PFI <0..15> RTSI <0..7> PXI_STAR...

  • Page 45: 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 46: 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 ni.com/info © National Instruments Corporation and enter the info code rdcanq 4-19...

  • Page 47: 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. Using a Digital Source To use AI Reference Trigger with a digital source, specify a source and an edge.

  • Page 48: 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 Simultaneous sampling Single-point analog input Finite analog input...

  • Page 49: Analog Output

    Figure 5-1 shows the analog output circuitry of a non-isolated S Series (NI 6124) device. Figure 5-2 shows the analog output circuitry of an isolated S Series (NI 6154) device. © National Instruments Corporation DAC0 AO 0 AO FIFO AO 1 DAC1 Figure 5-1.

  • Page 50: Minimizing Glitches On The Output Signal

    Chapter 5 Analog Output The main blocks featured in the S Series analog output circuitry are as follows: • • • • Minimizing Glitches on the Output Signal When you use a DAC to generate a waveform, you may observe glitches on the output signal.
  • Page 51 • © National Instruments Corporation Hardware-Timed Generations—With a hardware-timed generation, a digital hardware signal controls the rate of the generation. This signal can be generated internally on your device or provided externally. Hardware-timed generations have several advantages over software-timed generations: –...

  • Page 52: Analog Output Triggering

    Chapter 5 Analog Output Analog Output Triggering Analog output supports two different triggering actions: start and pause. 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 53 Figure 5-3 shows how AO 0 and AO 1 are wired on a non-isolated S Series device. Load Load Figure 5-4 shows how AO 0 is wired on an isolated S Series device. Load VOUT – © National Instruments Corporation AO 0 VOUT 0 – AO GND – VOUT 1 AO 1 Figure 5-3.

  • Page 54: 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. RTSI 7 Master Onboard Timebase Clock...

  • Page 55: 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 Polarity Polarity Figure 5-6.

  • Page 56: 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 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 57: 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 = 50 ns minimum = 23 ns minimum Figure 5-8.

  • Page 58: Using An Analog Source

    Chapter 5 Analog Output Figure 5-9 shows the timing requirements of the AO Start Trigger digital source. 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. For more information, refer to the Chapter 11, Triggering.

  • Page 59: 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 Triggering with an Analog Source Single-point generation Finite generation...

  • Page 60: Digital I/O

    • • • • © National Instruments Corporation Digital I/O for Non-Isolated Devices—NI 6124 devices have eight lines of bidirectional DIO lines on Port 0, and 16 PFI signals that can function as static DIO lines. Digital I/O for Isolated Devices—NI 6154 devices have six...

  • Page 61: 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 DO.x Direction Control DI Waveform...

  • Page 62: Digital Waveform Triggering For Non-Isolated Devices

    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 devices do not have an independent DI or DO Start AI Start Trigger initiates AI Sample Clock and DI Sample Clock.

  • Page 63: 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) the P0.<0..7> terminals and store the result in the DI waveform acquisition FIFO.

  • Page 64: 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 PXI_STAR Analog Comparison Event (an analog trigger) You can generate digital waveforms on the Port 0 DIO lines.
  • Page 65 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: • • • • •...

  • Page 66: I/O Protection For Non-Isolated Devices

    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 Each DIO and PFI signal is protected against overvoltage, 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 67: Di Change Detection For Non-Isolated Devices

    Chapter 6 Digital I/O DI Change Detection for Non-Isolated Devices (NI 6124 Only) DIO signals. Figure 6-3 shows a block diagram of the DIO change detection circuitry. P0.0 Synch P0.7 Synch You can enable the DIO change detection circuitry to detect rising edges, falling edges, or either edge individually on each DIO line.

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

    Digital output applications include sending TTL signals and driving external devices, such as the LED shown in the figure. © National Instruments Corporation The DIO change detection circuitry can interrupt a user section of Chapter 11, Triggering. By routing the Change Detection The DIO signals, P0.<0..7>, PFI <0..7>/P1.<0..7>, and...

  • Page 69: Getting Started With Dio Applications In Software On Non-Isolated Devices

    Chapter 6 Digital I/O Exceeding the maximum input voltage ratings, which are listed in the Caution specifications document for each non-isolated DAQ-STC2 S Series device, can damage the DAQ device and the computer. NI is not liable for any damage resulting from such signal connections.

  • Page 70: 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 S Series isolated devices contain ten lines of unidirectional Isolation Barrier...

  • Page 71: I/O Protection For Isolated Devices

    Chapter 6 Digital I/O I/O Protection for Isolated Devices (NI 6154 Only) under-voltage, and over-current conditions as well as ESD events. However, you should avoid these fault conditions by following these guidelines: • • • • Connecting Digital I/O Signals on Isolated Devices (NI 6154 Only) PFI <6..9>/P1.<0..3>, are referenced to D GND.

  • Page 72: Getting Started With Dio Applications In Software On Isolated Devices

    • 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 PFI <6..9>/P1.<0..3> PFI <0..5>/P0.<0..5> D GND Isolated S Series Device Figure 6-6.
  • Page 73 Input Selection Muxes Input Selection Muxes Input Selection Muxes © National Instruments Corporation Counter 0 Counter 0 Source (Counter 0 Timebase) Counter 0 Gate Counter 0 Internal Output Counter 0 Aux...

  • Page 74: 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 Counter/Timer Pinouts Counter Input Applications Counting Edges In edge counting applications, the counter counts edges on its Source after the counter is armed.

  • Page 75: Buffered (Sample Clock) Edge Counting

    Figure 7-4 shows an example of buffered edge counting. Notice that counting begins when the counter is armed, which occurs before the first active edge on Gate. © National Instruments Corporation Counter Armed Pause Trigger (Pause When Low)

  • Page 76: 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: • • • For information about connecting counter signals, refer to the Counter/Timer Pinouts Pulse-Width Measurement In pulse-width measurements, the counter measures the width of a pulse on...

  • Page 77: 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 GATE SOURCE Counter Value Figure 7-5.

  • Page 78: Period Measurement

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

  • Page 79: 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 (Discard) Figure 7-8. Buffered Period Measurement Duplicate Count Prevention section.

  • Page 80: 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 81: Frequency Measurement

    You can choose one of the following methods depending on your application: • • © National Instruments Corporation section. Method 1: Measure Low Frequency with One Counter—In this method, you measure one period of your signal using a known timebase. This method is good for low frequency signals.
  • Page 82 Chapter 7 Counters • NI 6124/6154 User Manual 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.
  • Page 83 Pulse Gate Source Pulse-Width Measurement • © National Instruments Corporation Figure 7-12 illustrates this method. Another option would be to measure the width of a known period instead of a known pulse. Width of Pulse (T) Pulse Width of Pulse Frequency of F1 = Figure 7-12.

  • Page 84: Choosing A Method For Measuring Frequency

    Chapter 7 Counters Choosing a Method for Measuring Frequency The best method to measure frequency depends on several factors including the expected frequency of the signal to measure, the desired accuracy, how many counters are available, and how long the measurement can take.
  • Page 85 Error % • • • © National Instruments Corporation Method 1 uses only one counter. It is a good method for many applications. However, the accuracy of the measurement decreases as the frequency increases. Consider a frequency measurement on a 50 kHz signal using an 80 MHz Timebase.

  • Page 86: 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 Number of Counters Method Used 1 or 2 For information about connecting counter signals, refer to the Counter/Timer Pinouts Position Measurement You can use the counters to perform position measurements with quadrature encoders or two-pulse encoders.
  • Page 87 You can program this reload to occur in any one of the four phases in a quadrature cycle. © National Instruments Corporation Figure 7-14 shows a quadrature cycle and the resulting increments and decrements for X1 encoding. When channel A leads channel B, the increment occurs on the rising edge of channel A.

  • Page 88: 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 89: 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 section. Counter Armed...

  • Page 90: 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 91: 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 GATE SOURCE...

  • Page 92: 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). 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 93: 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 GATE (Start Trigger) SOURCE Figure 7-24.

  • Page 94: 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 95: 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) © National Instruments Corporation Frequency Output Timebase Frequency Generator Divisor (1–16) Figure 7-27. Frequency Generator Block Diagram Figure 7-28.

  • Page 96: 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 97: 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 GATE D2 = D1 + ΔD Figure 7-29.

  • Page 98: 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 99: 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 RTSI <0..7> PFI <0..15> AI Reference Trigger (ai/ReferenceTrigger)

  • Page 100: 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 101: 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 RTSI <0..7> PFI <0..15> AI Reference Trigger (ai/ReferenceTrigger)

  • Page 102: 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 103: Counter Triggering

    • • • © National Instruments Corporation Arm Start Trigger—To begin any counter input or output function, you must first enable, or arm, the counter. Software can arm a counter or configure counters to be armed on a hardware signal. Software calls this hardware signal the Arm Start Trigger.

  • Page 104: 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 105: 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 Figure 7-30. Filter Example rddfms...

  • Page 106: Duplicate Count Prevention

    Chapter 7 Counters 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. Prescaling can be used for event counting provided it is acceptable to have an error of up to seven (or one).

  • Page 107: 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 Synchronization Modes © National Instruments Corporation Gate Source Buffer Figure 7-32.

  • Page 108: 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. Counter Value Example Application That Prevents Duplicate Count With duplicate count prevention enabled, the counter synchronizes both the Source and Gate signals to the 80 MHz Timebase.

  • Page 109: When To Use Duplicate Count Prevention

    S Series devices use one of three synchronization methods: • • • © National Instruments Corporation You are making a counter measurement. You are using an external signal (such as PFI x) as the counter Source. The frequency of the external source is 20 MHz or less.

  • Page 110: 80 Mhz Source Mode

    Chapter 7 Counters In DAQmx, the device uses 80 MHz source mode if you perform the following: • • Otherwise, the mode depends on the signal that drives Counter n Source. Table 7-5 describes the conditions for each mode. Duplicate Count Prevention Enabled Position Measurement All Except Position...

  • Page 111: 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 112: Programmable Function Interfaces (Pfi)

    Each PFI can be individually configured as the following: • • • • © National Instruments Corporation PFI for Non-Isolated Devices—NI 6124 devices have 16 PFI pins in addition to eight lines of bidirectional DIO signals. PFI for Isolated Devices—NI 6154 devices have 10 equivalent directional PFI pins that can be independently configured as an input or output.

  • Page 113: 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 Direction Control To Input Timing Signal Selectors When a terminal is used as a timing input or output signal, it is called PFI x (where x is an integer from 0 to 15).
  • Page 114 (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 Chapter 8 Isolation Barrier...

  • Page 115: 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. to any of the following signals: • • • • • • • •...

  • Page 116: Using Pfi Terminals As Static Digital Inputs And Outputs

    Using PFI Terminals as Static Digital Inputs and Outputs You can configure PFI terminals to be static digital input or output terminals: • • © National Instruments Corporation Chapter 8 AO Start Trigger (ao/StartTrigger) Counter n Source Counter n Gate...

  • Page 117: 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 Filters You can enable a programmable debouncing filter on each PFI, RTSI, or PXI_STAR signal.
  • Page 118 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 code © National Instruments Corporation Chapter 8 Table 8-1. Filters Pulse Width Needed to...

  • Page 119: 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: • • • •...
  • Page 120 • 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 Chapter 8 NI 6154 Devices—By default, the digital output lines (P1.<0..3>/PFI <6..9>) are disabled (high impedance) at power up.

  • Page 121: Digital Routing And Clock Generation

    RTSI <0..7> Clock PXI_CLK10 PXI_STAR © National Instruments Corporation Manages the flow of data between the bus interface and the acquisition/generation sub-systems (analog input, analog output, digital I/O, and the counters). The digital routing circuitry uses FIFOs (if present) in each sub-system to ensure efficient data movement.

  • Page 122: 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: • • 20 MHz Timebase The 20 MHz Timebase normally generates many of the AI and AO timing signals.

  • Page 123: 10 Mhz Reference Clock

    RTSI bus and setting their sample clock rates to the same value. © National Instruments Corporation Chapter 9 Digital Routing and Clock Generation NI 6124/6154 User Manual...

  • Page 124: Real-Time System Integration (Rtsi)

    • • 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 125: Using Rtsi As Outputs

    • • • • • • • • © National Instruments Corporation Chapter 9 Table 9-1. RTSI Signals (Continued) Terminal Terminal 2 Figure 9-2. S Series PCI Device RTSI Pinout AI Start Trigger (ai/StartTrigger) AI Reference Trigger (ai/ReferenceTrigger) AI Convert Clock* (ai/ConvertClock)

  • Page 126: Using Rtsi Terminals As Timing Input Signals

    Chapter 9 Digital Routing and Clock Generation • • • • • 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 127 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 Chapter 9 Table 9-2. Filters...

  • Page 128: 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 code PXI Clock and Trigger Signals (NI 6124 Only) PXI Express devices.

  • Page 129: Pxi_Star Filters

    Table 9-3. N (Filter Clocks Filter Setting 125 ns 6.425 μs 2.56 ms Disabled © National Instruments Corporation Chapter 9 You can enable a programmable debouncing filter on each Table 9-3. Filters Pulse Width Needed to Guaranteed to...

  • Page 130: 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 PXI_STAR Terminal Filter Clock...

  • Page 131: Bus Interface

    (NI 6124 Only) Express slot or PXI hybrid slots in PXI Express chassis. PXI specifications are developed by the PXI System Alliance ( © National Instruments Corporation PXI Express PXI clock and trigger signals are only available on PXI and...

  • Page 132: 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 133: 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 A software command A condition on an external digital signal...

  • Page 134: Triggering With An Analog Source

    Chapter 11 Triggering Figure 11-1 shows a 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: • • • Triggering with an Analog Source (NI 6124 Only) signal.

  • Page 135: Analog Input Channel

    Note (NI 6154 Only) Analog Trigger Types (NI 6124 Only) modes: • © National Instruments Corporation You can select any analog input channel to drive the Analog Trigger Accuracy section. The output of the Analog Trigger Detection circuit is the...
  • Page 136 Chapter 11 Triggering • NI 6124/6154 User Manual 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 137 Then signal must go below low threshold before Analog Comparison Event asserts Analog Comparison Event © National Instruments Corporation For the trigger to assert, the signal must first be below the low threshold, then go above the high threshold. The trigger stays asserted until the signal returns below the low threshold.

  • Page 138: Analog Trigger Accuracy

    Chapter 11 Triggering • Bottom Analog Comparison Event Analog Trigger Accuracy (NI 6124 Only) trigger source to the output of programmable trigger DACs. When you configure the level (or the high and low limits in window trigger mode), the device adjusts the output of the trigger DACs. Refer to the specifications document for your device to find the accuracy and resolution of the analog trigger DACs.

  • Page 139: Device-Specific Information

    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 NI 6154 Four simultaneously sampling analog inputs at 4 MS/s with one 16-bit...
  • Page 140 Appendix A Device-Specific Information The AO channels do not have analog or digital filtering hardware and do produce Note 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 141 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 Signal Descriptions © National Instruments Corporation Table A-1. Default NI-DAQmx Counter/Timer Pins Counter/Timer Signal CTR 0 SRC...
  • Page 142 Appendix A Device-Specific Information NI 6124 Block Diagram Figure A-2 shows the NI 6124 block diagram. PGIA Cal Relay Control(0) PGIA Cal Relay Control(1) PGIA Cal Relay Control(2) PGIA Cal Relay Control(3) Calibration Control Calibration Calibration Multiplexer Voltage Reference 16-Bit DAC 0 16-Bit DAC 1...
  • Page 143 If you want to develop your own cable, follow these guidelines for best results: • • • © National Instruments Corporation SH68-68-EPM—shielded cable SH68-68R1-EP—shielded cable with one right angle connector SH6868—shielded 68-conductor cable RC68-68—unshielded cable CB-68LP, CB-68LPR—low-cost screw terminal block SCB-68—shielded screw terminal block with breadboard areas...
  • Page 144 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. • • • For more information about the connectors used for DAQ devices, refer to the KnowledgeBase document, Specifications and Manufacturers for Board Mating Connectors, by going to code...
  • Page 145 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 Four differential 16-bit analog inputs Four 16-bit analog output channels...
  • Page 146 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. Counter/Timer Signal NI 6124/6154 User Manual AI 0+ AI 1– AI 2+ AI 3– AO 0+ AO 1–...
  • Page 147 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 Signal Descriptions © National Instruments Corporation Default Pin Number (Name) CTR 0 B CTR 1 SRC...
  • Page 148 Appendix A Device-Specific Information NI 6154 Block Diagram Figure A-4 shows the NI 6154 block diagram. Circuit PGIA AO 0 PGIA 16-Bit PGIA AO 1 PGIA 16-Bit PGIA AO 2 PGIA 16-Bit PGIA AO 3 PGIA 16-Bit NI 6154 Cables and Accessories This section describes some of the cable and accessory options for the NI 6154.
  • Page 149 • • 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 6154 Isolation and Digital Isolators The NI 6154 is an isolated data acquisition device. As shown in Figure 2-2,...

  • Page 150: 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 151 NI 6154 Specifications Refer to the NI 6154 Specifications for more detailed information about the device. © National Instruments Corporation Improved accuracy—Isolation improves measurement accuracy by physically preventing ground loops. Ground loops, a common source of error and noise, are the result of a measurement system having multiple grounds at different potentials.

  • Page 152: Technical Support And Professional Services

    Technical Support and Professional Services Visit the following sections of the award-winning National Instruments Web site at • • • © National Instruments Corporation for technical support and professional services: ni.com Support—Technical support at following resources: – Self-Help Technical Resources—For answers and solutions,...
  • Page 153 Appendix B Technical Support and Professional Services • • If you searched your local office or NI corporate headquarters. Phone numbers for our worldwide offices are listed at the front of this manual. You also can visit the Worldwide Offices section of office Web sites, which provide up-to-date contact information, support phone numbers, email addresses, and current events.
  • Page 154 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 Value –12 –9 –6 –3 NI 6124/6154 User Manual...
  • Page 155 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 156 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 ground. Glossary NI 6124/6154 User Manual...
  • Page 157 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 158 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 ground. Glossary NI 6124/6154 User Manual...
  • Page 159 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 160 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 Glossary NI 6124/6154 User Manual...
  • Page 161 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 162 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 Glossary NI 6124/6154 User Manual...
  • Page 163 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 164 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 Glossary NI 6124/6154 User Manual...
  • Page 165 11-4 analog input circuitry, 4-2 data acquisition methods, 4-4 fundamentals, 4-1 overview, 4-1 © National Instruments Corporation signals AI Convert Clock, 4-16 AI Convert Clock Timebase, 4-17 AI Reference Trigger, 4-19 AI Sample Clock, 4-14 AI Sample Clock Timebase, 4-16...
  • Page 166 Index applications counter input, 7-2 counter output, 7-19 edge counting, 7-2 arm start trigger, 7-31 block diagram NI 6124, A-4 NI 6154, A-10 PFI input circuitry, 8-3 PFI output circuitry, 8-3 buffered edge counting, 7-3 period measurement, 7-7 position measurement, 7-17 pulse-width measurement, 7-5 semi-period measurement, 7-8 two-signal edge-separation...
  • Page 167 7-20 synchronization modes, 7-37 timing signals, 7-25 triggering, 7-31 counting edges, 7-2 © National Instruments Corporation DAC FIFO, 5-2 DACs, 5-2 hardware for isolated devices, 2-3 hardware for non-isolated devices, 2-2 system overview, 2-1...
  • Page 168 Index triggering, 11-1 waveform acquisition, 6-3 waveform generation, 6-5 digital I/O, 6-1 block diagram, 6-2 circuitry, 6-2 connecting signals, 6-9 DI change detection, 6-8 digital waveform generation, 6-5 getting started with applications in software, 6-10 I/O protection, 6-7 programmable power-up states, 6-7 static DIO, 6-2 waveform acquisition, 6-3 waveform triggering, 6-3...
  • Page 169 I/O connector NI 6124, A-2 NI 6154, A-8 signal descriptions isolated devices, 3-2 non-isolated devices, 3-1 © National Instruments Corporation I/O protection, 6-7, 8-8 input coupling, 4-2 input polarity and range, 4-3 input signals using PFI terminals as, 8-4 using RTSI terminals as, 9-6...
  • Page 170 7-9 averaged, 7-9 minimizing glitches on the output signal, 5-2 MITE and DAQ-PnP, 10-1 multiple device synchronization, 9-3 mux, 4-2 National Instruments support and services, B-1 .NET languages documentation, xiv NI 6124, A-4 analog output, A-1 block diagram, A-4...
  • Page 171 10-1 PXI_CLK10, 9-8 PXI_STAR filters, 9-9 trigger, 9-8 quadrature encoders, 7-14 real-time system integration bus, 9-4 reciprocal frequency measurement, 7-11 © National Instruments Corporation reference clock 10 MHz, 9-3 external, 9-2 related documentation, xii retriggerable single pulse generation, 7-20 routing...
  • Page 172 Index signals AI Convert Clock, 4-16 AI Convert Clock Timebase, 4-17 AI Reference Trigger, 4-19 AI Sample Clock, 4-14 AI Sample Clock Timebase, 4-16 AI Start Trigger, 4-18 Change Detection Event, 6-8 connecting digital I/O, 6-9 connecting PFI input, 8-6 Counter n A, 7-28 Counter n Aux, 7-28 Counter n B, 7-28...
  • Page 173 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 waveform generation digital, 6-5 triggering, 6-3 waveform generation timing signals AO Pause Trigger, 5-10...

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