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OPERATING INSTRUCTIONS AND SPECIFICATIONS

NI 9237

4-Channel, 24-Bit Half/Full-Bridge Analog Input Module

 

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Summary of Contents for NI 9237

Page 1: ...OPERATING INSTRUCTIONS AND SPECIFICATIONS NI 9237 4 Channel 24 Bit Half Full Bridge Analog Input Module ni com manuals Deutsch Français ...

Page 2: ... and programming the system refer to the system documentation Visit ni com info and enter cseriesdoc for information about C Series documentation Note The safety guidelines and specifications in this document are specific to the NI 9237 The other components in the system might not meet the same safety ratings and specifications Refer to the documentation for each component in the system to determi...

Page 3: ... Class I Division 2 Groups A B C D T4 hazardous locations Class I Zone 2 AEx nC IIC T4 and Ex nC IIC T4 hazardous locations and nonhazardous locations only Follow these guidelines if you are installing the NI 9237 in a potentially explosive environment Not following these guidelines may result in serious injury or death Caution Do not disconnect I O side wires or connectors unless power has been s...

Page 4: ...e following limits Capacitance 0 2 μF max Inductance 80 mH max Special Conditions for Hazardous Locations Use in Europe This equipment has been evaluated as EEx nC IIC T4 equipment under DEMKO Certificate No 03 ATEX 0324020X Each module is marked II 3G and is suitable for use in Zone 2 hazardous locations If you are using the NI 9237 in Gas Group IIC hazardous locations or in ambient temperatures ...

Page 5: ...earch for the LR certificate or look for the Lloyd s Register mark on the module Caution To meet radio frequency emission requirements for marine applications use shielded cables and install the system in a metal enclosure Suppression ferrites must be installed on power supply inputs near power entries to modules and controllers Power supply and module cables must be separated on opposite sides of...

Page 6: ...s 6 ni com Connecting the NI 9237 The NI 9237 has four RJ 50 receptacles that provide connections for four half or full bridges Figure 1 NI 9237 Pin Assignments SC AI AI RS RS EX EX T T SC 1 2 3 4 5 6 7 8 9 10 Ch0 Ch3 EX EX EX EX Ch 0 Ch 1 Ch 2 Ch 3 ...

Page 7: ...quarter bridge with the NI 9237 if you add a resistor externally to create a half bridge You also can use a quarter bridge with the NI 9237 if you use the NI 9944 or NI 9945 Quarter Bridge Completion Accessory Visit ni com and search for the NI 9944 and NI 9945 Quarter Bridge Completion Accessories for more information about these accessories and how to purchase them Note National Instruments does...

Page 8: ...in Note When you insert or remove a new sensor from the NI 9237 slight changes in the excitation voltages can cause a mismatch between the internal half bridge completion resistors and the half bridge sensors which results in a change in the measurement offsets National Instruments recommends performing bridge calibrations of quarter or half bridge sensors after connecting all sensors to the NI 92...

Page 9: ... National Instruments Corp 9 NI 9237 Operating Instructions and Specifications Figure 2 Connecting a Half or Full Bridge to the NI 9237 EX EX SC SC RS RS T T AI AI TEDS NI 9237 ...

Page 10: ... device that is biased at any voltage within the NI 9237 rejection range of earth ground Refer to the Specifications section for more information about the common mode rejection ratio CMRR You also can connect floating signals to the NI 9237 If you connect floating signals to the NI 9237 National Instruments recommends connecting the EX signal to the earth ground or shield for better noise rejecti...

Page 11: ... NI 9237 provides two mechanisms to correct for these errors remote sensing and shunt calibration Remote Sensing Remote sensing continuously and automatically corrects for errors in excitation leads and generally is most appropriate for half and full bridge sensors Long wire and small gauge wire have greater resistance which can result in gain error The resistance in the wires that connect the exc...

Page 12: ...fications 12 ni com circuit Refer to Figure 3 for an illustration of how to connect remote sense wires to the NI 9237 Figure 3 Connecting Remote Sense Wires to the NI 9237 EX EX RS RS Rbridge Rlead Rlead Rbridge Rbridge Rbridge NI 9237 AI AI ...

Page 13: ...istors the NI 9237 senses the actual bridge voltage and eliminates the gain errors caused by the resistance of the EX and EX leads Shunt Calibration Shunt calibration can correct for errors from the resistance of both the excitation wiring and wiring in the individual resistors of the bridge Remote sensing corrects for resistances from the EX pins on the NI 9237 to the sensor and shunt calibration...

Page 14: ...y shunting or connecting a large resistor of known value across one arm of the bridge creating a known strain induced change in resistance You can then measure the output of the bridge and compare it to the expected voltage value You can use the results to correct gain errors in the entire measurement path or to simply verify general operation to gain confidence in the setup Use a stable signal wh...

Page 15: ...n provide up to 150 mW of excitation power Unless you supply external excitation voltage National Instruments recommends that you set the excitation voltage to a value that keeps the total power below 150 mW The NI 9237 automatically reduces internal excitation voltages as needed to stay below 150 mW total power The power consumed by a single bridge is where R is the total resistance of the bridge...

Page 16: ...al excitation source to the NI 9237 Understanding NI 9237 Filtering The NI 9237 uses a combination of analog and digital filtering to provide an accurate representation of in band signals while rejecting out of band signals The filters discriminate between signals based on the frequency range or bandwidth of the signal The three important bandwidths to consider are the passband the stopband and th...

Page 17: ...passband have frequency dependent gain or attenuation The small amount of variation in gain with respect to frequency is called the passband flatness The digital filters of the NI 9237 adjust the frequency range of the passband to match the data rate Therefore the amount of gain or attenuation at a given frequency depends on the data rate Figure 4 shows typical passband flatness for the NI 9237 ...

Page 18: ...s for the NI 9237 Stopband The filter significantly attenuates all signals above the stopband frequency The primary goal of the filter is to prevent aliasing Therefore the stopband frequency scales precisely with the data Frequency Data Rate 0 5 0 4 0 025 0 000 0 025 0 050 0 3 0 2 0 1 0 Gain dB ...

Page 19: ...quals the data rate minus the stopband frequency Understanding NI 9237 Data Rates The frequency of a master timebase fM controls the data rate fs of the NI 9237 The NI 9237 includes an internal master timebase with a frequency of 12 8 MHz but the module also can accept an external master timebase or export its own master timebase To synchronize the data rate of an NI 9237 with other modules that u...

Page 20: ...r timebase of 12 8 MHz the result is data rates of 50 kS s 25 kS s 16 67 kS s and so on down to 1 613 kS s depending on the value of n When using an external timebase with a frequency other than 12 8 MHz the NI 9237 has a different set of data rates Note The cRIO 9151 R Series Expansion chassis does not support sharing timebases between modules Sleep Mode This module supports a low power sleep mod...

Page 21: ... is in sleep mode you cannot communicate with the modules In sleep mode the system consumes minimal power and may dissipate less heat than it does in normal mode Refer to the Specifications section for more information about power consumption and thermal dissipation Specifications The following specifications are typical for the range 40 to 70 C unless otherwise noted Input Characteristics Number ...

Page 22: ...rate range fs using internal master timebase Minimum 1 613 kS s Maximum 50 kS s Data rate range fs using external master timebase Minimum 390 625 S s Maximum 51 3 kS s Data rates1 fs n 1 2 31 Typical input range 25 mV V Scaling coefficient 2 9802 nV V per LSB 1 The data rate must remain within the appropriate data rate range Refer to the Understanding NI 9237 Data Rates section for more informatio...

Page 23: ...0 6 μV V per C 3 3 V excitation 0 5 μV V per C 5 V excitation 0 3 μV V per C 10 V excitation 0 2 μV V per C Measurement Conditions Percent of Reading Gain Error Percent of Range Offset Error Calibrated typ 25 C 5 C 0 05 0 05 Calibrated max 40 to 70 C 0 20 0 25 Uncalibrated typ 25 C 5 C 0 20 0 1 Uncalibrated max 40 to 70 C 0 60 0 35 Before offset null or shunt calibration Range equals 25 mV V ...

Page 24: ... 0 to 1 kHz 0 001 fin 0 to 20 kHz 0 1 Input delay 38 4 fs 4 8 μs Passband Frequency 0 45 fs Flatness 0 1 dB max Stopband Frequency 0 55 fs Rejection 100 dB Alias free bandwidth 0 45 fs Oversample rate 64 fs Input Signal Frequency fin Gain Phase Typical Maximum Maximum 0 to 1 kHz 0 15 0 3 0 125 kHz fin 1 to 20 kHz 0 4 1 1 ...

Page 25: ... Hz 140 dB Relative to EX fin 0 to 1 kHz 85 dB SFDR 1 kHz 60 dBFS 106 dB Total Harmonic Distortion THD 1 kHz 20 dBFS 100 dB 8 kHz 20 dBFS 90 dB 1 Rejection by analog prefilter of signal frequencies at oversample rate 2 Measured with a balanced cable Shielded cables that are not twisted pair may be significantly unbalanced To improve the balance of shielded twisted pair cables NI recommends twistin...

Page 26: ...alk fin 1 kHz 110 dB fin 10 kHz 100 dB Excitation Internal voltage 2 5 V 3 3 V 5 0 V 10 0 V Internal power 150 mW max External voltage 2 V to 10 V Excitation Voltage Density nV Vrms per Total fin 0 to 25 kHz μV Vrms Total fin 0 to 1 kHz nV Vrms 2 5 V 8 1 3 250 3 3 V 6 1 0 190 5 V 4 0 6 130 10 V 2 0 3 65 1Hz ...

Page 27: ...Ω MTBF 603 359 hours at 25 C Bellcore Issue 2 Method 1 Case 3 Limited Part Stress Method Note Contact NI for Bellcore MTBF specifications at other temperatures or for MIL HDBK 217F specifications Power Requirements Power consumption from chassis Active mode 740 mW max Sleep mode 25 μW max Thermal dissipation at 70 C Active mode 740 mW max Sleep mode 25 μW max ...

Page 28: ...s Between any two pins 30 V max Isolation Channel to channel None Channel to earth ground Continuous 60 VDC Measurement Category I Withstand 1 000 Vrms verified by a 5 s dielectric withstand test Measurement Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS voltage MAINS is a hazardous live electrical supply syste...

Page 29: ...ent limited energy parts of equipment circuits powered by regulated low voltage sources and electronics Caution Do not connect the NI 9237 to signals or use for measurements within Measurement Categories II III or IV Hazardous Locations U S UL Class I Division 2 Groups A B C D T4 Class I Zone 2 AEx nC IIC T4 Canada C UL Class I Division 2 Groups A B C D T4 Class I Zone 2 Ex nC IIC T4 Europe DEMKO ...

Page 30: ... UL and other safety certifications refer to the product label or the Online Product Certification section Electromagnetic Compatibility This product meets the requirements of the following EMC standards for electrical equipment for measurement control and laboratory use EN 61326 IEC 61326 Class A emissions Basic immunity EN 55011 CISPR 11 Group 1 Class A emissions AS NZS CISPR 11 Group 1 Class A ...

Page 31: ...meets the essential requirements of applicable European Directives as follows 2006 95 EC Low Voltage Directive safety 2004 108 EC Electromagnetic Compatibility Directive EMC Online Product Certification Refer to the product Declaration of Conformity DoC for additional regulatory compliance information To obtain product certifications and the DoC for this product visit ni com certification search b...

Page 32: ... 2 27 30 g 11 ms half sine 50 g 3 ms half sine 18 shocks at 6 orientations Environmental National Instruments C Series modules are intended for indoor use only but may be used outdoors if installed in a suitable enclosure Refer to the manual for the chassis you are using for more information about meeting these specifications Operating temperature IEC 60068 2 1 IEC 60068 2 2 40 to 70 C Storage tem...

Page 33: ...mitted to designing and manufacturing products in an environmentally responsible manner NI recognizes that eliminating certain hazardous substances from our products is beneficial to the environment and to NI customers For additional environmental information refer to the NI and the Environment Web page at ni com environment This page contains the environmental regulations and directives with whic...

Page 34: ...National Instruments WEEE initiatives visit ni com environment weee Calibration You can obtain the calibration certificate and information about calibration services for the NI 9237 at ni com calibration Calibration interval 1 year ᄤֵᙃѻક ᶧ ࠊㅵ ࡲ Ё RoHS Ё ᅶ National Instruments ヺড়Ё ᄤֵᙃ ѻકЁ䰤ࠊՓ ᶤѯ ᆇ 䋼ᣛҸ RoHS DŽ Ѣ National Instruments Ё RoHS ড়㾘ᗻֵᙃˈ䇋ⱏᔩ ni com environment rohs_chinaDŽ For information about...

Page 35: ...3504 National Instruments also has offices located around the world to help address your support needs For telephone support in the United States create your service request at ni com support and follow the calling instructions or dial 512 795 8248 For telephone support outside the United States contact your local branch office Australia 1800 300 800 Austria 43 662 457990 0 Belgium 32 0 2 757 0020...

Page 36: ... refer to the appropriate location Help Patents in your software the patents txt file on your media or the National Instruments Patent Notice at ni com patents Korea 82 02 3451 3400 Lebanon 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 7 495 783 6851 Sin...

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