National Instruments NI 781 R Series Скачать руководство пользователя

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Chapter 2

Hardware Overview of the NI 78xxR

National Instruments Corporation

2-9

R Series Intelligent DAQ User Manual

Figure 2-5 summarizes the recommended input mode for both types of
signal sources.

Figure 2-5.

Summary of Analog Input Connections

+
–

–

AI<

AISENSE

AIGND<

+
–

–

AI<

AISENSE

AIGND<

See text for information on bias resistors.

+
–

–

AI<

AIGND<

+
–

–

+ V

–

AIGND

Ground-loop losses, V

, are added to

measured signal.

NOT RECOMMENDED

+
–

–

AI<

>(+)

AI<

>(–)

AIGND<

+
–

–

AI<

>(+)

AI<

>(–)

AIGND<

See text for information on bias resistors.

Signal Source Type

Floating Signal Source

(Not Connected to Building Ground)

Grounded Signal Source

Examples
• Ungrounded Thermocouples
• Signal Conditioning with
Isolated

Outputs

• Battery Devices

Examples
• Plug-in Instruments with
Nonisolated

Outputs

Input

Differential

(DIFF)

Single-Ended—

Ground

Referenced

(RSE)

Single-Ended—

Nonreferenced

(NRSE)

Содержание NI 781 R Series

Страница 1: ...PXI 7842...

Страница 2: ...Intelligent DAQ NI R Series Intelligent DAQ User Manual NI 781xR 783xR NI 784xR and NI 785xR Devices R Series Intelligent DAQ User Manual June 2008 370489F 01...

Страница 3: ...ebanon 961 0 1 33 28 28 Malaysia 1800 887710 Mexico 01 800 010 0793 Netherlands 31 0 348 433 466 New Zealand 0800 553 322 Norway 47 0 66 90 76 60 Poland 48 22 3390150 Portugal 351 210 311 210 Russia 7...

Страница 4: ...ctronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instruments Corporati...

Страница 5: ...t of Communications DOC Changes or modifications not expressly approved by NI could void the user s authority to operate the equipment under the FCC Rules Class A Federal Communications Commission Thi...

Страница 6: ...4 User Defined I O Resources 1 4 Device Embedded Logic and Processing 1 4 Reconfigurable I O Architecture 1 5 Reconfigurable I O Applications 1 6 Software Development 1 6 LabVIEW FPGA Module 1 6 LabVI...

Страница 7: ...ded Signal Sources NRSE Input Mode 2 15 Common Mode Signal Rejection Considerations 2 16 Analog Output 2 16 Connecting Analog Output Signals 2 17 Digital I O 2 17 Connecting Digital I O Signals 2 17 R...

Страница 8: ...This icon denotes a note which alerts you to important information This icon denotes a caution which advises you of precautions to take to avoid injury data loss or a system crash When this symbol is...

Страница 9: ...re and software you use for your application you could have any of several types of documentation The documentation includes the following documents Getting Started with R Series Intelligent DAQ This...

Страница 10: ...s to the LabVIEW Help and other Real Time Module documents for more information as you create the real time application To access this document refer to ni com manuals In LabVIEW 8 0 or later you can...

Страница 11: ...er LabVIEW contains an extensive library of VIs and example programs for use with R Series devices To access the NI Example Finder open LabVIEW and select Help Find Examples then select Hardware Input...

Страница 12: ...f the device You can change the functionality of the FPGA on the R Series device in LabVIEW using the LabVIEW FPGA Module to create and download a custom virtual Table 1 1 NI 78xxR R Series Intelligen...

Страница 13: ...connected between devices R Series PXI devices access the RTSI bus through the PXI trigger lines implemented on the PXI backplane Refer to the NI R Series Intelligent DAQ Specifications available at n...

Страница 14: ...functions in hardware Refer to Chapter 2 Hardware Overview of the NI 78xxR for descriptions of the I O resources on the NI 78xxR Reconfigurable I O Concept R Series Intelligent DAQ devices are based...

Страница 15: ...endent timed loops with separate I O resources User Defined I O Resources You can create your own custom measurements using the fixed I O resources For example one application might require an event c...

Страница 16: ...ents using the LabVIEW FPGA Module The FPGA logic provides timing triggering processing and custom I O measurements Each fixed I O resource used by the application uses a small portion of the FPGA log...

Страница 17: ...s of FPGA VIs Software Development You can use LabVIEW with the LabVIEW FPGA Module to program the NI 78xxR To develop real time applications that control the NI 78xxR use LabVIEW with the LabVIEW Rea...

Страница 18: ...onal Instruments NI RIO RIO Device Setup Help LabVIEW Real Time Module The LabVIEW Real Time Module extends the LabVIEW development environment to deliver deterministic real time performance You can w...

Страница 19: ...to the NI SCB 68 terminal block to provide higher signal integrity and noise immunity SHC68 68 RDIO NI Recommended 1 2 NI SCB 68 High performance shielded cable wired specifically for signal connectio...

Страница 20: ...maged in any way If the device is damaged return it to NI for repair Do not substitute parts or modify the device except as described in this document Use the device only with the chassis modules acce...

Страница 21: ...a description of installation categories Measurement Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS3 voltage Thi...

Страница 22: ...t in fixed installations distribution boards and circuit breakers Other examples are wiring including cables bus bars junction boxes switches socket outlets in the fixed installation and stationary mo...

Страница 23: ...k diagram for the NI 7830R Figure 2 3 shows a block diagram for the NI 7831R 7833R 784xR 785xR Figure 2 1 NI 781xR Block Diagram Configuration Configuration Control Connector 0 DIO Connector 1 DIO Con...

Страница 24: ...put Mode Mux AISENSE AIGND Calibration Mux Voltage Reference Temperature Sensor Calibration DACs 2 x4 Channels 16 Bit DAC Digital I O 16 User Configurable FPGA on RIO Devices Bus Interface Data Addres...

Страница 25: ...AO channels 56 bidirectional DIO lines that you can configure individually for input or output and a Virtex II XC2V1000 FPGA AI AI PCI PXI CompactPCI Bus Input Mux Instrumentation Amplifier Input Mod...

Страница 26: ...t independent 16 bit AI channels eight independent 16 bit AO channels and 96 bidirectional DIO lines that you can configure individually for input or output The NI PXI 7851R has a Virtex 5 LX30 FPGA t...

Страница 27: ...uses two AI lines The positive input pin connects to the positive terminal of the onboard instrumentation amplifier The negative input pin connects to the negative input of the instrumentation amplifi...

Страница 28: ...t of the instrumentation amplifier for each channel In RSE input mode the negative input of the instrumentation amplifier for each channel is internally connected to AIGND In NRSE input mode the AISEN...

Страница 29: ...ive and negative inputs of the instrumentation amplifier The instrumentation amplifier converts two input signals to a signal that is the difference between the two input signals The amplifier output...

Страница 30: ...ut signal varies as the source floats out of the common mode input range Ground Referenced Signal Sources A ground referenced signal source is connected to the building system ground so it is already...

Страница 31: ...resistors V1 AI i AIGND i V1 AI Vg AIGND Ground loop losses Vg are added to measured signal NOT RECOMMENDED V1 AI i AI i AIGND i V1 AI i AI i AIGND i See text for information on bias resistors Signal...

Страница 32: ...rence signal or return connects to the negative input of the instrumentation amplifier Use differential input connections for any channel that meets any of the following conditions The input signal is...

Страница 33: ...he ground potential difference between the signal source and the NI 783xR 784xR 785xR ground shown as Vcm in Figure 2 6 In addition the instrumentation amplifier can reject common mode noise pickup in...

Страница 34: ...e side of the signal to the positive input of the instrumentation amplifier and connecting the negative side of the signal to AIGND and to the negative input of the instrumentation amplifier without r...

Страница 35: ...strumentation amplifier to work If the source is AC coupled capacitively coupled the instrumentation amplifier needs a resistor between the positive input and AIGND If the source has low impedance cho...

Страница 36: ...785xR should not supply one In single ended input modes electrostatic and magnetic noise couples into the signal connections more than in differential input modes The coupling is the result of differ...

Страница 37: ...tial difference between the NI 783xR 784xR 785xR ground and the signal ground appears as a common mode signal at both the positive and negative inputs of the instrumentation amplifier The instrumentat...

Страница 38: ...com manuals for more information about input ranges Analog Output The bipolar output range of the NI 783xR 784xR 785xR AO channels is fixed at 10 V Some applications require that the AO channels powe...

Страница 39: ...for either input or output When the system powers on the DIO lines are at high impedance To set another power on state you can configure the NI 78xxR to load a VI when the system powers on The VI can...

Страница 40: ...ernal pull up resistor to 5 V This resistor pulls up the 3 3 V digital output from the NI 78xxR to 5 V CMOS logic levels Refer to the NI R Series Intelligent DAQ Specifications available at ni com man...

Страница 41: ...f the switch shown in Figure 2 11 Digital output applications include sending TTL or LVCMOS signals and driving external devices such as the LED shown in Figure 2 11 The NI 78xxR SHC68 68 RDIO cable c...

Страница 42: ...xamples of high frequency or edge sensitive signals include clock trigger pulse width modulation PWM encoder and counter signals Examples of static signals or non edge sensitive low frequency signals...

Страница 43: ...the RTSI bus is connected in parallel to all the other RTSI devices on the bus only one device should drive a particular RTSI trigger line at a time For example if one NI PXI 78xxR is configured to se...

Страница 44: ...enable the local bus lines on an adjacent device if the device drives anything other than 0 3 3V LVTTL signal levels on the NI PXI 781xR 783xR Enabling the lines in this way can damage the NI PXI 781...

Страница 45: ...of switches on the NI PXI 783xR For normal operation SW1 is in the OFF position To prevent a VI stored in flash memory from loading to the FPGA at power up move SW1 to the ON position as shown in Figu...

Страница 46: ...Chapter 2 Hardware Overview of the NI 78xxR R Series Intelligent DAQ User Manual 2 24 ni com Figure 2 13 Switch Location on the NI PCI 781xR SW1 SW2 SW3...

Страница 47: ...erview of the NI 78xxR National Instruments Corporation 2 25 R Series Intelligent DAQ User Manual Figure 2 14 Switch Location on the NI PXI 781xR NI PXI 7811R Reconfigurable I O CONNECTOR 2 DIO CONNEC...

Страница 48: ...Chapter 2 Hardware Overview of the NI 78xxR R Series Intelligent DAQ User Manual 2 26 ni com Figure 2 15 Switch Location on the NI PCI 783xR SW1 SW2 SW3...

Страница 49: ...PXI 783xR Figure 2 17 Switch Settings Complete the following steps to prevent a VI stored in flash memory from loading to the FPGA 1 Power off and unplug the PXI CompactPCI chassis or PCI computer 2...

Страница 50: ...xR 783xR is powered on with SW1 in the ON position the analog circuitry does not return properly calibrated data Move the switch to the ON position only while you are using software to reconfigure the...

Страница 51: ...ce Doing so can damage the device and the computer NI is not liable for damage resulting from such a connection The power rating on most devices is 4 75 to 5 25 VDC at 1 A Refer to the NI R Series Int...

Страница 52: ...ual 2 30 ni com 3 Replace the broken fuse while referring to Figure 2 18 for the fuse locations Figure 2 18 NI 784xR 785xR Replacement Fuse Location 4 Reinstall the PCI or PXI device into the computer...

Страница 53: ...for signals traveling through areas with large magnetic fields or high electromagnetic interference Route signals to the device carefully Keep cabling away from noise sources The most common noise sou...

Страница 54: ...ost difficult and most accurate Loading Calibration Constants The NI 783xR 784xR 785xR is factory calibrated before shipment at approximately 25 C to the levels indicated in the device specifications...

Страница 55: ...re a small amount of gain error and self calibration is sufficient The flash memory on the NI 783xR 784xR 785xR stores the results of an internal calibration so the CalDACs automatically load with the...

Страница 56: ...elligent DAQ User Manual To externally calibrate your device use an external reference several times more accurate than the device itself For more information on externally calibrating your NI 783xR 7...

Страница 57: ...to the NI 78xxR I O connectors Figure A 1 shows the I O connector pin assignments and locations for NI PCI 7811R 7813R and NI PXI 7811R 7813R Figure A 2 shows the I O connector pin assignments and loc...

Страница 58: ...12 DIO13 DIO14 DIO15 DIO16 DIO17 DIO18 DIO19 DIO20 DIO21 DIO22 DIO23 DIO24 DIO25 DIO26 DIO27 DIO29 DIO30 DIO32 DIO34 DIO36 DIO38 35 1 36 2 37 3 38 4 39 5 40 6 41 7 42 8 43 9 44 10 45 11 46 12 47 13 48...

Страница 59: ...0 55 21 56 22 57 23 58 24 59 25 60 26 61 27 62 28 63 29 64 30 65 31 66 32 67 33 68 34 1 No Connect on the NI 7830R DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND...

Страница 60: ...the reference point for single ended measurements in RSE configuration and the bias current return point for differential measurements All three ground references AIGND AOGND and DGND are connected to...

Страница 61: ...e Input Output Protection Volts On Off Source mA at V Sink mA at V Rise Time Bias 5V DO Analog Signals NI 783xR 784xR 785xR Only AI 0 7 AI 10 G in parallelwith 100 pF 42 35 2 nA AI 0 7 AI 10 G in para...

Страница 62: ...e when using 5B signal conditioning The other 26 pin header contains all the NI 783xR 784xR 785xR analog output signals You can plug this connector directly into a 5B backplane for AO signal condition...

Страница 63: ...AOGND4 AO5 AO6 AOGND6 AO7 No Connect No Connect No Connect AOGND1 No Connect No Connect AOGND3 No Connect No Connect AOGND5 No Connect No Connect AOGND7 No Connect 2 4 6 8 10 12 14 16 18 20 22 24 26...

Страница 64: ...the NSC68 5050 Cable 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 DIO23 DIO22 DIO21 DIO20 DIO19 DIO18 DI...

Страница 65: ...Figure B 1 for the general purpose switch configuration Figure B 1 General Purpose Switch Configuration for the SCB 68 Terminal Block After configuring the SCB 68 switches you can connect the I O sig...

Страница 66: ...ndard Service Program Membership This program entitles members to direct access to NI Applications Engineers via phone and email for one to one technical support as well as exclusive access to on dema...

Страница 67: ...product by visiting ni com certification Calibration Certificate If your product supports calibration you can obtain the calibration certificate for your product at ni com calibration If you searched...

Страница 68: ...lossary Symbol Prefix Value p pico 10 12 n nano 10 9 micro 10 6 m milli 10 3 k kilo 103 M mega 106 G giga 109 Numbers Symbols Degrees Greater than Greater than or equal to Less than Less than or equal...

Страница 69: ...nalog voltage to a digital number AI Analog input AI i Analog input channel signal AIGND Analog input ground signal AISENSE Analog input sense signal AO Analog output AO i Analog output channel signal...

Страница 70: ...ode signal usually expressed in decibels dB common mode voltage Any voltage present at the instrumentation amplifier inputs with respect to amplifier ground CompactPCI Refers to the core specification...

Страница 71: ...to from computer memory DNL Differential nonlinearity A measure in LSB of the worst case deviation of code widths from their ideal value of 1 LSB DO Digital output E EEPROM Electrically erasable prog...

Страница 72: ...aphical programming language that uses icons instead of lines of text to create programs LSB Least significant bit M m Meter max Maximum MIMO Multiple input multiple output min Minimum MIO Multifuncti...

Страница 73: ...vary with respect to the measurement system ground O OUT Output pin A counter output pin where the counter can generate various TTL pulse waveforms P PCI Peripheral Component Interconnect A high perfo...

Страница 74: ...e I O rms Root mean square RSE Referenced single ended mode All measurements are made with respect to a common reference measurement system or a ground Also called a grounded measurement system RTSI R...

Страница 75: ...unction of the temperature TTL Transistor transistor logic two s complement Given a number x expressed in base 2 with n digits to the left of the radix point the base 2 number 2n x V V Volts VDC Volts...

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