Page 3 - Important Information
Important Information Warranty The NI 6238/6239 is warranted against defects in materials and workmanship for a period of three years from the date of shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace equipment that proves to be de...
Page 5 - Contents; About This Manual
© National Instruments Corporation v NI 6238/6239 User Manual Contents About This Manual Conventions ................................................................................................................... xiiiRelated Documentation.............................................................
Page 11 - Glossary
Contents © National Instruments Corporation xi NI 6238/6239 User Manual Chapter 11Bus Interface DMA Controllers ........................................................................................................... 11-1PXI Considerations ............................................................
Page 12 - Conventions
© National Instruments Corporation xiii NI 6238/6239 User Manual About This Manual The NI 6238/6239 User Manual contains information about using the NI 6238 and NI 6239 M Series data acquisition (DAQ) devices with NI-DAQmx 8.1 and later. National Instruments 6238/6239 devices feature up to eight dif...
Page 13 - Related Documentation
About This Manual NI 6238/6239 User Manual xiv ni.com italic Italic text denotes variables, emphasis, a cross-reference, or an introduction to a key concept. Italic text also denotes text that is a placeholder for a word or value that you must supply. monospace Text in this font denotes text or char...
Page 14 - LabVIEW
About This Manual © National Instruments Corporation xv NI 6238/6239 User Manual The C Function Reference Help describes functions and attributes. The NI-DAQmx for Linux Configuration Guide provides configuration instructions, templates, and instructions for using test panels. Note All NI-DAQmx docu...
Page 15 - LabWindows; ANSI C without NI Application Software
About This Manual NI 6238/6239 User Manual xvi ni.com tools. Refer to the following locations on the Contents tab of the LabVIEW Help for information about NI-DAQmx: • Getting Started»Getting Started with DAQ —Includes overview information and a tutorial to learn how to take an NI-DAQmx measurement ...
Page 16 - .NET Languages without NI Application Software; Device Documentation and Specifications; Training Courses
About This Manual © National Instruments Corporation xvii NI 6238/6239 User Manual .NET Languages without NI Application Software The NI Measurement Studio Help contains function reference and measurement concepts for using the Measurement Studio NI-DAQmx .NET and Visual C++ class libraries. This he...
Page 17 - Getting Started; Installing Other Software; Device Pinouts
© National Instruments Corporation 1-1 NI 6238/6239 User Manual 1 Getting Started M Series NI 6238/6239 devices feature eight differential analog input (AI) channels, two analog output (AO) channels, two counters, six lines of digital input (DI), and four lines of digital output (DO). If you have no...
Page 18 - Device Specifications; Device Accessories and Cables
Chapter 1 Getting Started NI 6238/6239 User Manual 1-2 ni.com Device Specifications Refer to the NI 6238/6239 Specifications , available on the NI-DAQ Device Document Browser or ni.com/manuals , for more detailed information on NI 6238/6239 devices. Device Accessories and Cables NI offers a variety ...
Page 19 - DAQ System Overview; DAQ Hardware
© National Instruments Corporation 2-1 NI 6238/6239 User Manual 2 DAQ System Overview Figure 2-1 shows a typical DAQ system, which includes sensors, transducers, cables that connect the various devices to the accessories, the M Series device, programming software, and PC. The following sections cove...
Page 21 - Calibration Circuitry; Sensors and Transducers
Chapter 2 DAQ System Overview © National Instruments Corporation 2-3 NI 6238/6239 User Manual Calibration Circuitry The M Series analog inputs and outputs can self calibrate to correct gain and offset errors. You can calibrate the device to minimize AI and AO errors caused by time and temperature dr...
Page 22 - Cables and Accessories; Custom Cabling
Chapter 2 DAQ System Overview NI 6238/6239 User Manual 2-4 ni.com Cables and Accessories NI offers a variety of products to use with NI 6238/6239 devices, including cables, connector blocks, and other accessories, as follows: • Cables and cable assemblies – Shielded – Unshielded ribbon • Screw termi...
Page 23 - Programming Devices in Software
Chapter 2 DAQ System Overview © National Instruments Corporation 2-5 NI 6238/6239 User Manual Programming Devices in Software National Instruments measurement devices are packaged with NI-DAQ driver software, an extensive library of functions and VIs you can call from your application software, such...
Page 24 - Connector Information; I/O Connector Signal Descriptions
© National Instruments Corporation 3-1 NI 6238/6239 User Manual 3 Connector Information The I/O Connector Signal Descriptions and RTSI Connector Pinout sections contain information on M Series connectors. Refer to Appendix A, Device-Specific Information , for device I/O connector pinouts. I/O Connec...
Page 26 - RTSI Connector Pinout
Chapter 3 Connector Information © National Instruments Corporation 3-3 NI 6238/6239 User Manual RTSI Connector Pinout Refer to the RTSI Connector Pinout section of Chapter 10, Digital Routing and Clock Generation , for information on the RTSI connector. CAL+ — — External Calibration Positive Referen...
Page 27 - Analog Input; Analog Input Circuitry
© National Instruments Corporation 4-1 NI 6238/6239 User Manual 4 Analog Input Figure 4-1 shows the analog input circuitry of NI 6238 and NI 6239 devices. Figure 4-1. NI 6238/6239 Analog Input Circuitry Analog Input Circuitry I/O Connector You can connect analog input signals to the M Series device ...
Page 28 - Analog Input Range
Chapter 4 Analog Input NI 6238/6239 User Manual 4-2 ni.com for all input ranges. The NI-PGIA can amplify or attenuate an AI signal to ensure that you use the maximum resolution of the ADC. M Series devices use the NI-PGIA to deliver high accuracy even when sampling multiple channels with small input...
Page 29 - Method 1
Chapter 4 Analog Input © National Instruments Corporation 4-3 NI 6238/6239 User Manual M Series devices use a calibration method that requires some codes (typically about 5% of the codes) to lie outside of the specified range. This calibration method improves absolute accuracy, but it increases the ...
Page 30 - Method 2
Chapter 4 Analog Input NI 6238/6239 User Manual 4-4 ni.com Figure 4-2. Analog Current Input Connection Method 1 Method 2 Method 2, shown in Figure 4-3, ties the AI – input to AI GND. When measuring current up to 20 mA, this type of connection ensures that the voltage level on both the positive and n...
Page 34 - Multichannel Scanning Considerations; Use Short High-Quality Cabling; Minimize Current Step between Adjacent Channels
Chapter 4 Analog Input NI 6238/6239 User Manual 4-8 ni.com Multichannel Scanning Considerations M Series devices can scan multiple channels at high rates and digitize the signals accurately. However, you should consider several issues when designing your measurement system to ensure the high accurac...
Page 35 - Avoid Scanning Faster Than Necessary
Chapter 4 Analog Input © National Instruments Corporation 4-9 NI 6238/6239 User Manual For example, suppose all channels in a system use a –20 to 20 mA input range. The signals on channels 0, 2, and 4 vary between 18 and 19 mA. The signals on channels 1, 3, and 5 vary between –18 and 0 mA. Scanning ...
Page 36 - Analog Input Data Acquisition Methods; Software-Timed Acquisitions; Buffered
Chapter 4 Analog Input NI 6238/6239 User Manual 4-10 ni.com Analog Input Data Acquisition Methods When performing analog input measurements, you either can perform software-timed or hardware-timed acquisitions. Hardware-timed acquisitions can be buffered or non-buffered. Software-Timed Acquisitions ...
Page 37 - Analog Input Triggering; Field Wiring Considerations
Chapter 4 Analog Input © National Instruments Corporation 4-11 NI 6238/6239 User Manual samples has been written out, the generation stops. If you use a reference trigger, you must use finite sample mode. Continuous acquisition refers to the acquisition of an unspecified number of samples. Instead o...
Page 38 - Analog Input Timing Signals
Chapter 4 Analog Input NI 6238/6239 User Manual 4-12 ni.com mainly to AI signal routing to the device, although they also apply to signal routing in general. Minimize noise pickup and maximize measurement accuracy by using individually shielded, twisted-pair wires to connect AI signals to the device...
Page 41 - AI Sample Clock Signal
Chapter 4 Analog Input © National Instruments Corporation 4-15 NI 6238/6239 User Manual example, four. The value decrements with each pulse on ai/SampleClock, until the value reaches zero. The sample counter is then loaded with the number of posttriggered samples, in this example, three. Figure 4-10...
Page 42 - Using an Internal Source; Using an External Source
Chapter 4 Analog Input NI 6238/6239 User Manual 4-16 ni.com You can specify an internal or external source for ai/SampleClock. You also can specify whether the measurement sample begins on the rising edge or falling edge of ai/SampleClock. Using an Internal Source One of the following internal signa...
Page 43 - Other Timing Requirements; AI Sample Clock Timebase Signal
Chapter 4 Analog Input © National Instruments Corporation 4-17 NI 6238/6239 User Manual Other Timing Requirements Your DAQ device only acquires data during an acquisition. The device ignores ai/SampleClock when a measurement acquisition is not in progress. During a measurement acquisition, you can c...
Page 45 - Using a Delay from Sample Clock to Convert Clock
Chapter 4 Analog Input © National Instruments Corporation 4-19 NI 6238/6239 User Manual finished. It then reloads itself in preparation for the next ai/SampleClock pulse. Using an External Source Use one of the following external signals as the source of ai/ConvertClock: • Input PFI <0..5> • R...
Page 47 - AI Convert Clock Timebase Signal; AI Hold Complete Event Signal
Chapter 4 Analog Input © National Instruments Corporation 4-21 NI 6238/6239 User Manual Figure 4-13. Single External Signal Driving ai/SampleClock and ai/ConvertClock Simultaneously AI Convert Clock Timebase Signal The AI Convert Clock Timebase (ai/ConvertClockTimebase) signal is divided down to pro...
Page 48 - Routing AI Start Trigger to an Output Terminal
Chapter 4 Analog Input NI 6238/6239 User Manual 4-22 ni.com AI Start Trigger Signal Use the AI Start Trigger (ai/StartTrigger) signal to begin a measurement acquisition. A measurement acquisition consists of one or more samples. If you do not use triggers, begin a measurement with a software command...
Page 50 - Using a Digital Source; AI Pause Trigger Signal
Chapter 4 Analog Input NI 6238/6239 User Manual 4-24 ni.com Using a Digital Source To use ai/ReferenceTrigger with a digital source, specify a source and an edge. The source can be any of the following signals: • Input PFI <0..5> • RTSI <0..7> • PXI_STAR The source also can be one of sev...
Page 51 - Getting Started with AI Applications in Software
Chapter 4 Analog Input © National Instruments Corporation 4-25 NI 6238/6239 User Manual Routing AI Pause Trigger Signal to an Output Terminal You can route ai/PauseTrigger out to RTSI <0..7>. Note Pause triggers are only sensitive to the level of the source, not the edge. Getting Started with ...
Page 52 - Analog Output; Analog Output Circuitry
© National Instruments Corporation 5-1 NI 6238/6239 User Manual 5 Analog Output NI 6238/6239 devices have two AO channels controlled by a single clock and capable of waveform generation. Figure 5-1 shows the analog current output circuitry of NI 6238 and NI 6239 devices. Figure 5-1. NI 6238/6239 Ana...
Page 53 - Analog Output Data Generation Methods; Software-Timed Generations
Chapter 5 Analog Output NI 6238/6239 User Manual 5-2 ni.com DACs. It allows you to download the points of a waveform to your M Series device without host computer interaction. AO Sample Clock The AO Sample Clock signal reads a sample from the DAC FIFO and generates the AO voltage. Isolation Barrier ...
Page 55 - Analog Output Triggering; Connecting Analog Current Output Signals
Chapter 5 Analog Output NI 6238/6239 User Manual 5-4 ni.com the buffer at a fast enough rate to keep up with the generation, the buffer will underflow and cause an error. Analog Output Triggering Analog output supports two different triggering actions: • Start trigger • Pause trigger A digital trigg...
Page 56 - Analog Output Timing Signals; AO Start Trigger Signal
Chapter 5 Analog Output © National Instruments Corporation 5-5 NI 6238/6239 User Manual Maximum Working Voltage section of the NI 6238/6239 Specifications . Exceeding the maximum input supply voltage or maximum working voltage of AO signals distorts the measurement results. Exceeding the maximum inp...
Page 57 - AO Pause Trigger Signal
Chapter 5 Analog Output NI 6238/6239 User Manual 5-6 ni.com Using a Digital Source To use ao/StartTrigger, specify a source and an edge. The source can be one of the following signals: • A pulse initiated by host software • Input PFI <0..5> • RTSI <0..7> • ai/ReferenceTrigger • ai/StartT...
Page 59 - AO Sample Clock Signal
Chapter 5 Analog Output NI 6238/6239 User Manual 5-8 ni.com You also can specify whether the samples are paused when ao/PauseTrigger is at a logic high or low level. Routing AO Pause Trigger Signal to an Output Terminal You can route ao/PauseTrigger out to RTSI <0..7>. AO Sample Clock Signal U...
Page 61 - Getting Started with AO Applications in Software
Chapter 5 Analog Output NI 6238/6239 User Manual 5-10 ni.com ao/SampleClockTimebase is not available as an output on the I/O connector. You might use ao/SampleClockTimebase if you want to use an external sample clock signal, but need to divide the signal down. If you want to use an external sample c...
Page 62 - Digital Input and Output; Programmable Power-Up States
© National Instruments Corporation 6-1 NI 6238/6239 User Manual 6 Digital Input and Output NI 6238/6239 devices have six static digital input lines, P0.<0..5>. These lines also can be used as PFI inputs. In addition, the NI 6238/6239 devices have four static digital output lines, P1.<0..3&g...
Page 63 - Connecting Digital I/O Signals
Chapter 6 Digital Input and Output NI 6238/6239 User Manual 6-2 ni.com Connecting Digital I/O Signals The DI signals P0.<0..5> are referenced to P0.GND and DO signals P1.<0..3> are referenced to P1.GND. Figures 6-1 and 6-2 show P0.<0..5> and P1.<0..3> on the NI 6238 and the N...
Page 64 - Logic Conventions
Chapter 6 Digital Input and Output © National Instruments Corporation 6-3 NI 6238/6239 User Manual Figure 6-2. NI 6239 Digital I/O Connections (DO Sink) Caution Exceeding the maximum input voltage or maximum working voltage ratings, which are listed in the NI 6238/6239 Specifications , can damage th...
Page 65 - Getting Started with DIO Applications in Software
Chapter 6 Digital Input and Output NI 6238/6239 User Manual 6-4 ni.com Getting Started with DIO Applications in Software You can use NI 6238/6239 devices in the following digital I/O applications: • Static digital input • Static digital output Note For more information about programming digital I/O ...
Page 66 - Counters
© National Instruments Corporation 7-1 NI 6238/6239 User Manual 7 Counters NI 6238/6239 devices have two general-purpose 32-bit counter/timers and one frequency generator, as shown in Figure 7-1. The general-purpose counter/timers can be used for many measurement and pulse generation applications. C...
Page 68 - Counter Input Applications; Counting Edges
Chapter 7 Counters © National Instruments Corporation 7-3 NI 6238/6239 User Manual Counter Input Applications Counting Edges In edge counting applications, the counter counts edges on its Source after the counter is armed. You can configure the counter to count rising or falling edges on its Source ...
Page 70 - Controlling the Direction of Counting
Chapter 7 Counters © National Instruments Corporation 7-5 NI 6238/6239 User Manual Non-Cumulative Buffered Edge Counting Non-cumulative edge counting is similar to buffered (sample clock) edge counting. However, the counter resets after each active edge of the Sample Clock. You can route the Sample ...
Page 71 - Pulse-Width Measurement; Buffered Pulse-Width Measurement
Chapter 7 Counters NI 6238/6239 User Manual 7-6 ni.com Pulse-Width Measurement In pulse-width measurements, the counter measures the width of a pulse on its Gate input signal. You can configure the counter to measure the width of high pulses or low pulses on the Gate signal. You can route an interna...
Page 72 - Period Measurement
Chapter 7 Counters © National Instruments Corporation 7-7 NI 6238/6239 User Manual The counter counts the number of edges on the Source input while the Gate input remains active. On each trailing edge of the Gate signal, the counter stores the count in a hardware save register. A DMA controller tran...
Page 73 - Buffered Period Measurement
Chapter 7 Counters NI 6238/6239 User Manual 7-8 ni.com Single Period Measurement With single period measurement, the counter counts the number of rising (or falling) edges on the Source input occurring between two active edges of the Gate input. On the second active edge of the Gate input, the count...
Page 74 - Semi-Period Measurement; Single Semi-Period Measurement
Chapter 7 Counters © National Instruments Corporation 7-9 NI 6238/6239 User Manual Figure 7-9. Buffered Period 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 corr...
Page 75 - Frequency Measurement
Chapter 7 Counters NI 6238/6239 User Manual 7-10 ni.com Buffered Semi-Period Measurement In buffered semi-period measurement, on each edge of the Gate signal, the counter stores the count in a hardware save register. A DMA controller transfers the stored values to host memory. The counter begins cou...
Page 79 - Choosing a Method for Measuring Frequency
Chapter 7 Counters NI 6238/6239 User Manual 7-14 ni.com Figure 7-14. Method 3 Then route the Counter 0 Internal Output signal to the Gate input of Counter 1. You can route a signal of known frequency (F2) to the Counter 1 Source input. F2 can be 80MHzTimebase. For signals that might be slower than 0...
Page 81 - Position Measurement; X1 Encoding
Chapter 7 Counters NI 6238/6239 User Manual 7-16 ni.com For information on connecting counter signals, refer to the Default Counter Terminals section. Position Measurement You can use the counters to perform position measurements with quadrature encoders or two-pulse encoders. You can measure angula...
Page 82 - X4 Encoding; Channel Z Behavior
Chapter 7 Counters © National Instruments Corporation 7-17 NI 6238/6239 User Manual Figure 7-15. X1 Encoding X2 Encoding The same behavior holds for X2 encoding except the counter increments or decrements on each edge of channel A, depending on which channel leads the other. Each cycle results in tw...
Page 84 - Single Two-Signal Edge-Separation Measurement
Chapter 7 Counters © National Instruments Corporation 7-19 NI 6238/6239 User Manual For information on connecting counter signals, refer to the Default Counter Terminals section. Two-Signal Edge-Separation Measurement Two-signal edge-separation measurement is similar to pulse-width measurement, exce...
Page 86 - Counter Output Applications; Simple Pulse Generation; Single Pulse Generation with Start Trigger
Chapter 7 Counters © National Instruments Corporation 7-21 NI 6238/6239 User Manual Counter Output Applications Simple Pulse Generation Single Pulse Generation The counter can output a single pulse. The pulse appears on the Counter n Internal Output signal of the counter. You can specify a delay fro...
Page 88 - Pulse Train Generation
Chapter 7 Counters © National Instruments Corporation 7-23 NI 6238/6239 User Manual Pulse Train Generation Continuous Pulse Train Generation This function generates a train of pulses with programmable frequency and duty cycle. The pulses appear on the Counter n Internal Output signal of the counter....
Page 89 - Frequency Generation
Chapter 7 Counters NI 6238/6239 User Manual 7-24 ni.com Frequency Generation You can generate a frequency by using a counter in pulse train generation mode or by using the frequency generator circuit. Using the Frequency Generator The frequency generator can output a square wave at many different fr...
Page 90 - Frequency Division; Pulse Generation for ETS
Chapter 7 Counters © National Instruments Corporation 7-25 NI 6238/6239 User Manual Frequency Output can be routed out to any output PFI <6..9> or RTSI <0..7> terminal. All PFI terminals are set to high-impedance at startup. In software, program the frequency generator as you would progr...
Page 91 - Counter Timing Signals; Counter
Chapter 7 Counters NI 6238/6239 User Manual 7-26 ni.com frequency of the system. Figure 7-28 shows an example of pulse generation for ETS; the delay from the trigger to the pulse increases after each subsequent Gate active edge. Figure 7-28. Pulse Generation for ETS For information on connecting cou...
Page 92 - Routing a Signal to Counter
Chapter 7 Counters © National Instruments Corporation 7-27 NI 6238/6239 User Manual performing. Table 7-3 lists how this terminal is used in various applications. Routing a Signal to Counter n Source Each counter has independent input selectors for the Counter n Source signal. Any of the following s...
Page 96 - Routing Frequency Output to a Terminal; Default Counter Terminals
Chapter 7 Counters © National Instruments Corporation 7-31 NI 6238/6239 User Manual Routing Frequency Output to a Terminal You can route Frequency Output to any output PFI <6..9> terminal. All PFIs are set to high-impedance at startup. Default Counter Terminals By default, NI-DAQmx routes the ...
Page 97 - Counter Triggering; Arm Start Trigger; Start Trigger
Chapter 7 Counters NI 6238/6239 User Manual 7-32 ni.com Counter Triggering Counters support three different triggering actions—arm start, start, and pause. 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 confi...
Page 98 - Other Counter Features; Cascading Counters; Counter Filters
Chapter 7 Counters © National Instruments Corporation 7-33 NI 6238/6239 User Manual Other Counter Features Cascading Counters You can internally route the Counter n Internal Output and Counter n TC signal of each counter to the Gate inputs of the other counter. By cascading two counters together, yo...
Page 99 - Prescaling
Chapter 7 Counters NI 6238/6239 User Manual 7-34 ni.com The filter setting for each input can be configured independently. On power up, the filters are disabled. Figure 7-29 shows an example of a low-to-high transition on an input that has its filter set to 125 ns (N = 5). Figure 7-29. Filter Exampl...
Page 100 - Duplicate Count Prevention
Chapter 7 Counters © National Instruments Corporation 7-35 NI 6238/6239 User Manual Figure 7-30. 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 deter...
Page 102 - Example Application That Prevents Duplicate Count
Chapter 7 Counters © National Instruments Corporation 7-37 NI 6238/6239 User Manual Figure 7-32. Duplicate Count Example 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. By syn...
Page 103 - When To Use Duplicate Count Prevention; Enabling Duplicate Count Prevention in NI-DAQmx
Chapter 7 Counters NI 6238/6239 User Manual 7-38 ni.com counter value and Counter n Internal Output signals change synchronously to the 80 MHz Timebase. Note that duplicate count prevention should only be used if the frequency of the Source signal is 20 MHz or less. When To Use Duplicate Count Preve...
Page 104 - Other Internal Source Mode
Chapter 7 Counters © National Instruments Corporation 7-39 NI 6238/6239 User Manual Otherwise, the mode depends on the signal that drives Counter n Source. Table 7-6 describes the conditions for each mode. 80 MHz Source Mode In 80 MHz source mode, the device synchronizes signals on the rising edge o...
Page 107 - Using PFI Terminals as Timing Input Signals
Chapter 8 PFI NI 6238/6239 User Manual 8-2 ni.com Figure 8-2. NI 6238/6239 PFI Output Circuitry 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 9). When a terminal is used as a static digital input or output, it is called P0. x or P1. x...
Page 108 - Exporting Timing Output Signals Using PFI Terminals; Using PFI Terminals as Static Digital Inputs and Outputs
Chapter 8 PFI © National Instruments Corporation 8-3 NI 6238/6239 User Manual Exporting Timing Output Signals Using PFI Terminals You can route any of the following timing signals to any PFI <6..9> terminal. • AI Hold Complete Event • Counter n Source • Counter n Gate • Counter n Internal Outp...
Page 109 - PFI Filters
Chapter 8 PFI NI 6238/6239 User Manual 8-4 ni.com Figure 8-3. PFI Input Signals Connections PFI Filters You can enable a programmable debouncing filter on each PFI, RTSI, or PXI_STAR signal. When the filters are enabled, your device samples the input on each rising edge of a filter clock. M Series d...
Page 114 - Isolation and Digital Isolators
© National Instruments Corporation 9-1 NI 6238/6239 User Manual 9 Isolation and Digital Isolators NI 6232/6233 devices are isolated data acquisition devices. As shown in Figure 9-1, the analog input, analog output, counters, and PFI/static DIO circuitry are referenced to an isolated ground . The bus...
Page 115 - Digital Isolation
Chapter 9 Isolation and Digital Isolators NI 6238/6239 User Manual 9-2 ni.com The non-isolated ground is connected to the chassis ground of the PC or chassis where the device is installed. Each isolated ground is not connected to the chassis ground of the PC or chassis. The isolated ground can be at...
Page 116 - Reducing Common-Mode Noise
Chapter 9 Isolation and Digital Isolators © National Instruments Corporation 9-3 NI 6238/6239 User Manual • Improved safety —Isolation creates an insulation barrier so you can make measurements at elevated voltages while protecting against large transient voltage spikes. Reducing Common-Mode Noise I...
Page 118 - 0 MHz Timebase
Chapter 10 Digital Routing and Clock Generation NI 6238/6239 User Manual 10-2 ni.com Caution RTSI signals are not isolated from the chassis. 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 can be generated from eit...
Page 119 - 0 MHz Reference Clock; Synchronizing Multiple Devices
Chapter 10 Digital Routing and Clock Generation © National Instruments Corporation 10-3 NI 6238/6239 User Manual 10 MHz Reference Clock The 10 MHz reference clock can be used to synchronize other devices to your M Series device. The 10 MHz reference clock can be routed to the RTSI <0..7> termi...
Page 121 - Using RTSI as Outputs
Chapter 10 Digital Routing and Clock Generation © National Instruments Corporation 10-5 NI 6238/6239 User Manual Using RTSI as Outputs RTSI <0..7> are bidirectional terminals. As an output, you can drive any of the following signals to any RTSI terminal. • ai/StartTrigger • ai/ReferenceTrigger...
Page 122 - Using RTSI Terminals as Timing Input Signals
Chapter 10 Digital Routing and Clock Generation NI 6238/6239 User Manual 10-6 ni.com Using RTSI Terminals as Timing Input Signals You can use RTSI terminals to route external timing signals to many different M Series functions. Each RTSI terminal can be routed to any of the following signals. • AI C...
Page 123 - PXI Clock and Trigger Signals
Chapter 10 Digital Routing and Clock Generation © National Instruments Corporation 10-7 NI 6238/6239 User Manual The filter setting for each input can be configured independently. On power up, the filters are disabled. Figure 10-3 shows an example of a low-to-high transition on an input that has its...
Page 124 - PXI Triggers
Chapter 10 Digital Routing and Clock Generation NI 6238/6239 User Manual 10-8 ni.com PXI_CLK10 PXI_CLK10 is a common low-skew 10 MHz clock reference clock for synchronization of multiple modules in a PXI measurement or control system. The PXI backplane is responsible for generating PXI_CLK10 indepen...
Page 127 - Bus Interface; DMA Controllers
© National Instruments Corporation 11-1 NI 6238/6239 User Manual 11 Bus Interface The bus interface circuitry of NI 6238/6239 devices efficiently moves data between host memory and the measurement and acquisition circuits. NI 6238/6239 devices are available for the following platforms. • PCI • PXI N...
Page 128 - PXI Considerations; PXI and PXI Express
Chapter 11 Bus Interface NI 6238/6239 User Manual 11-2 ni.com Each DMA controller supports packing and unpacking of data through the FIFOs to connect different size devices and optimize PCI bus utilization and automatically handles unaligned memory buffers. PXI Considerations Note PXI clock and trig...
Page 129 - Using PXI with CompactPCI; Data Transfer Methods
Chapter 11 Bus Interface © National Instruments Corporation 11-3 NI 6238/6239 User Manual Using PXI with CompactPCI Using PXI-compatible products with standard CompactPCI products is an important feature provided by PXI Hardware Specification Revision 2.1 . If you use a PXI-compatible plug-in module...
Page 130 - Changing Data Transfer Methods between DMA and IRQ
Chapter 11 Bus Interface NI 6238/6239 User Manual 11-4 ni.com Interrupt Request (IRQ) IRQ transfers rely on the CPU to service data transfer requests. The device notifies the CPU when it is ready to transfer data. The data transfer speed is tightly coupled to the rate at which the CPU can service th...
Page 131 - Triggering; Triggering with a Digital Source
© National Instruments Corporation 12-1 NI 6238/6239 User Manual 12 Triggering A trigger is a signal that causes an action, such as starting or stopping the acquisition of data. When you configure a trigger, you must decide how you want to produce the trigger and the action you want the trigger to c...
Page 135 - NI 6238 Accessory and Cabling Options; RTSI
Appendix A Device-Specific Information © National Instruments Corporation A-3 NI 6238/6239 User Manual Note For more information about default NI-DAQmx counter inputs, refer to Connecting Counter Signals in the NI-DAQmx Help or the LabVIEW 8.x Help . NI 6238 Specifications Refer to the NI 6238/6239 ...
Page 136 - Cables; Custom Cabling and Connectivity
Appendix A Device-Specific Information NI 6238/6239 User Manual A-4 ni.com vision, and motion devices. Since PXI devices use PXI backplane signals for timing and synchronization, no cables are required. Cables In most applications, you can use the following cables: • SH37F-37M- x —37-pin female-to-m...
Page 138 - NI 6239 Accessory and Cabling Options
Appendix A Device-Specific Information NI 6238/6239 User Manual A-6 ni.com Note For more information about default NI-DAQmx counter inputs, refer to Connecting Counter Signals in the NI-DAQmx Help or the LabVIEW 8.x Help . NI 6239 Specifications Refer to the NI 6239 Specifications , available on the...
Page 140 - Troubleshooting
© National Instruments Corporation B-1 NI 6238/6239 User Manual B Troubleshooting This section contains some common questions about M Series devices. If your questions are not answered here, refer to the National Instruments KnowledgeBase at ni.com/kb . It contains thousands of documents that answer...
Page 164 - Index; Symbols; Numerics
© National Instruments Corporation I-1 NI 6238/6239 User Manual Index Symbols .NET languages documentation, xvii Numerics 10 MHz reference clock, 10-3100 kHz Timebase, 10-220 MHz Timebase, 10-280 MHz source mode, 7-3980 MHz Timebase, 10-2 A A/D converter, 4-2accessories, 2-4, A-3, A-6 choosing for y...
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