TBX-1328 High-Accuracy Isothermal Terminal Block Installation Guide
Contents
1. the measurements can be less accurate In MTEMP mode you must scan the temperature independently of the other 10 ni com channels on the SCXI 1120 D SCXI 1121 and SCXI 1126 You can read a temperature at the beginning of the test and use that value with the data that follows Using this method assumes that there are no temperature variations during the measurement period If there are temperature variations the measurements can be less accurate When using the SCXI 1125 MTEMP can be scanned from any location in the scan list Ss Notes Do not place switch S1 in DTEMP mode DTEMP mode is not supported When using SCXI 112X modules the TBX 1328 does not provide open thermocouple detection To provide open thermocouple detection you must provide a resistor to 5 V and another resistor to GND which defeats the isolation boundary and changes the specifications Temperature Sensor Output and Accuracy The TBX 1328 temperature sensor outputs 1 91 to 0 65 V from 0 to 50 C LabVIEW Measurement Studio and NI DAQ can convert a thermistor voltage to the thermistor temperature for the circuit diagram shown in Figure 5 i Note The circuit diagram in Figure 5 is optional information you can use if you want more details about the TBX 1328 temperature sensor 5 V 4 7 KQ 1 25V 2 5 kQ LM 4040 0 1 2 5V VTEMPOUT 0 1 T OTF P f a 5 kQ 210 pF 04 pF at 25 C 7516 V P Ld Figure 5 Temperature Sen2. 1121 module to measure current you must populate R lt 0 7 gt which corresponds to CH lt 0 7 gt Since the SCXI 1121 can measure a maximum current of 20 mA the minimum usable resistor value is R 10 V 20 mA 500 Q This terminal block does not provide strain relief for field signal wires Add strain relief insulation and padding for the wires if necessary 3 Replace the TBX 1328 terminal block cover and tighten the captive cover screws The signal connection is now complete J1 y GH gt QO 00060UC0U0UCUmD0UC mDLCONCOCO COCO GUU O a ee a a ee Y LI Z HIGH VOLTAGE ASSY183177B 01 CE NATIONAL a O gt NNRMS ce Sptemp Bis fo i ERTO 1996 cco MTEMPO T To RO RI R2 R3 R5 R6 R7 oo oo oo oo Fa oo oo o o4 7 P o EX1 CH3 J5 J6 H 8 J10 3Bo 5O J13 4 CH1 CHE R J4 _ J7 K A _ 0o O H gt B HHO og Og Be EX0 CH1 J3 Jg A O O JIZ JIT CHO CHO 3O Jg Og ZO Bc 11211120 1 TBX 1328 N 333 V GAT I MAX GHANNEL TO CHANNEL 250 V CAT Il MAX GHANNEL TO EARTH OPO O lt APUN Cover Mounting Nut 6 Serial Number Chassis Ground Screw Terminals 7 Current Receiver Resistor Sockets Backshell Mounting Kit R lt 0 7 gt Channel lt 0 7 gt Cable Connector 8 Signal Wire Screw Ter
3. SSS TBX 1328 High Accuracy Isothermal Terminal Block Installation Guide This guide describes how to install and use the TBX 1328 high accuracy isothermal terminal block with the SCXI 1120 D SCXI 1121 SCXI 1125 or SCXI 1126 modules Table 1 shows the signals you can use with each module Table 1 SCX Module and Signal Compatibility Millivolts Volts Medium Voltage 60 V High Voltage 250 V 1 000 V Current 4 to 20 mA Frequency to Voltage Thermocouple RTD Thermistor Strain Gauge Force Load Torque Module SCXI 1120 Yes Yes Yes Yes No Yes No N i Z SCXI 1120D Yes Yes Yes Yes No No No No No SCXI 1121 Yes Yes Yes Yes No Yes Yes Yes Yes SCXI 1125 Yes Yes Yes Yes No Yes No No No SCXI 1126 Yes Yes Yes Yes Yes No No No No The TBX 1328 high accuracy isothermal terminal block is a DIN rail mountable shielded terminal block with screw terminals to connect to the SCXI 1120 D SCXI 1121 SCXI 1125 or SCXI 1126 front connector The TBX 1328 has a high precision thermistor for precise cold junction compensation and isothermal copper planes that minimize the temperature gradients across the screw terminals when you take thermocouple measurements The TBX 1328 mounts on most European standard DIN EN mounting rails The terminal block has 24 screw terminals for easy signal connection Eight screw terminals connect to the SCXI chassis ground through the shield
4. e DIN rails ee DIN EN 50 022 DIN EN 50 035 Isothermal construction with cover attached Maximum Working Voltage Maximum working voltage refers to the signal voltage plus the common mode voltage Channel to earth ccccceeeeeseeeeeees Each channel must remain within 250 Vms or 250 VDC of ground Installation Category II Channel to channel ccceeeeeeeeeeeeees Each channel must remain within 250 Vms Or 250 VDC of the voltage applied to any other channel Installation Category I Environmental Operating temperature ee 0 to 50 C Storage temperature 0 eee 20 to 70 C H midity escossa cceestedieaeacenentonaacs 10 to 90 RH noncondensing Maximum altitude ccccccesccseeeeseeee 2 000 m Pollution Degree indoor use only 2 Safety The TBX 1328 is designed to meet the requirements of the following standards of safety for electrical equipment for measurement control and laboratory use e IEC 61010 1 EN 61010 1 e UL3111 1 UL61010B 1 e CAN CSA C22 2 No 1010 1 3 Note For UL and other safety certifications refer to the product label or to ni com National Instruments Corporation 9 TBX 1328 Installation Guide Electromagnetic Compatibility Emisio S nanasa EN 55011 Class A at 10 m FCC Part 15A above 1 GHz IMMUNITY iiias EN 61326 1997 A2 2001 Table 1 EMC EM 1 0 oc ccc cecceceseeeeesesesereeeeeees CE C Tick and FCC Part 15 Class A Compliant 3 Note For EMC com
5. ed to use mtemp In LabVIEW the channel string used to read Vrgypoyr depends on which module is connected to the TBX 1328 For more information about channel string arrays and the SCXI channel addressing syntax refer to the LabVIEW Measurements Manual which you can download at ni com manuals e With the SCXI 1120 D or SCXI 1121 use the address string obx scy mdz mtemp You cannot put this channel address string in the same channel string array as other channels on the module that you are addressing e With the SCXI 1125 use the address string obx scy mdz cjtemp You can put this channel address string in the same channel string array as other channels on the same SCXI 1125 module but it must be the first channel scanned on the SCXI 1125 Reading the Temperature Sensor in NI DAQ Refer to the NI DAQ Function Reference Manual for the description for reading the temperature sensor using the SCXI_Single_Chan_Setup SCXI_Change_Chan and SCXI_SCAN_Setup functions ay Note The method for scanning the temperature sensor on the SCXI 1125 with other channels on the same module using the SCXI_SCAN_Setup is the same as that of the SCXI 1102 Strain Measurement Considerations When you use the SCXI 1121 with the TBX 1328 to measure strain a small amount of voltage drop develops across the excitation wires in the SH32 32 A cable This voltage drop is due to the wire resistance and the current flow in these leads when a s
6. em and select Options from the last dialog box This icon denotes a note which alerts you to important information Bold text denotes items that you must select or click on in the software such as menu items and dialog box options Bold text also denotes parameter names Italic text denotes variables emphasis a cross reference or an introduction to a key concept This font also denotes text that is a placeholder for a word or value that you must supply Text in this font denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs subprograms subroutines device names functions operations variables filenames and extensions and code excerpts Italic text in this font denotes text that is a placeholder for a word or value that you must supply What You Need to Get Started TBX 1328 Installation Guide To set up and use the TBX 1328 you need the following items Q TBX 1328 high accuracy isothermal terminal block Q TBX 1328 High Accuracy Isothermal Terminal Block Installation Guide 0 Read Me First Safety and Radio Frequency Interference 2 ni com D Oovovo wv SCXI chassis and documentation One of the following modules and its documentation SCxXI 1120 D SCXI 1121 SCxXI 1125 SCXI 1126 SH32 32 A shielded cable assembl
7. front connector and secure the SH32 32 A cable by tightening both backshell mounting screws 6 Connect the other end of the cable assembly to the TBX 1328 terminal block connector and secure the SH32 32 A cable by tightening both backshell mounting screws 7 Reconnect the E Series DAQ device to the SCXI chassis TBX 1328 Installation Guide 6 ni com Figure 4 The Completed Installation Rack Mounting When you have completed the Installing the Terminal Block and Cable Assembly section you can mount the TBX assembly in the rack If you are using the National Instruments TBX Rack Mount Assembly refer to the TBX Rack Mount Installation Guide for instructions If you are not using this rack mount assembly complete the following steps to mount the TBX assembly directly onto the DIN rail 1 Snap the TBX terminal block onto the DIN rail with a firm push 2 Install the SCXI chassis using the appropriate chassis rack mount kit i Note To remove the TBX terminal block from the DIN rail place a flathead screwdriver into the slot above the terminal block base and pry it from the rail National Instruments Corporation 7 TBX 1328 Installation Guide Specifications All specifications are typical at 25 C unless otherwise specified Electrical Compatible modules SCXEM20 D enren 8 input channels SCXIFII2 spona ai 4 input channels 4 excitation output channels SCXPII2 Sena saaa aa 8 input channel
8. minals Assembly Number 9 Product Name Figure 1 TBX 1328 Terminal Block Parts Locator Diagram TBX 1328 Installation Guide 4 ni com Installing the Terminal Block and Cable Assembly After completing the Connecting the Signals section you can install the terminal block Complete the following steps to mount the SH32 32 A cable assembly and connect the TBX 1328 to the SCXI module while referring to Figures 2 through 4 as needed 1 Power off the SCXI chassis 2 Power off the computer that contains the E Series data acquisition DAQ device or disconnect the device from the SCXI chassis 3 Connect the TBX cable adapter to the appropriate SCXI module and secure it by tightening both thumb screws 1 M2 5 Mounting Screws 4 SCXI Chassis 2 Cable Assembly 5 TBX Cable Adapter 3 Thumb Screws Figure 2 Connecting the SH32 32 A Cable to the SCX Module National Instruments Corporation 5 TBX 1328 Installation Guide 4 Verify that the four backshell mounting ears on the cable assembly are in the position shown in Figure 3 If not remove the backshell mounting ears and install them in the position shown 1 Backshell Mounting Screws and Ears 4 Terminal Block Connector 2 Safety Ground Lugs 5 Signal Wire Entry 3 Captive Cover Screws Figure 3 Connecting the SH32 32 A Cable to the TBX 1328 Terminal Block 5 Connect one end of the cable assembly to the SCXI module
9. of the SH32 32 A cable With the SCXI 1120 D SCXI 1125 or SCXI 1126 the remaining eight pairs of screw terminals connect signals to the eight LabVIEW Measurement Studio National Instruments NI ni com NI DAQ and SCXI are trademarks of February 2003 National Instruments Corporation Product and company names mentioned herein are trademarks or trade names of 371207A 01 their respective companies For patents covering National Instruments products refer to the appropriate location Help Patents in your software the patents txt file on your CD orni com patents N NATIONAL 1996 2003 National Instruments Corp All rights reserved INSTRUMENTS Conventions SCXI module input channels With the SCXI 1121 four pairs of screw terminals connect signals to the four SCXI module input channels and four pairs connect to the SCXI module excitation channels There are eight resistor sockets R lt 0 7 gt for use with the 4 to 20 mA current input lt gt 3 bold italic monospace monospace italic The following conventions are used in this guide Angle brackets that contain numbers separated by an ellipsis represent a range of values associated with a bit or signal name for example DIO lt 3 0 gt The symbol leads you through nested menu items and dialog box options to a final action The sequence File Page Setup Options directs you to pull down the File menu select the Page Setup it
10. of R 0 21 Q m Figure 6 Full Bridge Strain Gauge Circuit Diagram National Instruments Corporation 15 TBX 1328 Installation Guide 3 Use the following formula to determine the total voltage drop V4rop in the SH32 32 A cable excitation leads Rr V Se V drop Rri RsG a For example if you have a 1 m SH32 32 A cable 120 Q full bridge strain gauge and V 3 333 V then the calculations from steps through 3 are 1 Rp 2 x 0 21 Q m x 1 m 0 42 Q multiply the cable length by two to take into consideration both the V and V lead resistances 2 Rsg 120 Q is the total equivalent bridge resistance as seen from the V terminals of the TBX 1328 3 Virop 11 6 mV which is 0 3 of the 3 333 V excitation Now calculate the voltage drop across the field signal wires you are connecting to the TBX 1328 Perform similar calculations for the field wires as you did for the cable Resistance can vary depending on the cable and field wires Add this error amount to the voltage drop across the SH32 32 A cable to get a total voltage drop You can compensate for this error along with any additional cable lead resistance introduced by the strain gauge connection wires One simple way of compensation is to calculate the lead resistance then input it along with the other strain gauge parameters into the conversion formula provided in your software applications such as LabVIEW and Measurement Studio To minimize resis
11. pliance operate this device with shielded cabling CE Compliance The TBX 1328 meets the essential requirements of applicable European Directives as amended for CE marking as follows Low Voltage Directive safety 73 23 EEC Electromagnetic Compatibility Directive EMC sser 89 336 EEC AA Note Refer to the Declaration of Conformity DoC for this product for any additional regulatory compliance information To obtain the DoC for this product click Declarations of Conformity Information at ni com hardref nsf Temperature Measurement Considerations TBX 1328 Installation Guide The TBX 1328 provides high accuracy temperature measurements for isolation modules such as the SCXI 1120 D SCXI 1121 and SCXI 1125 The TBX 1328 provides connectivity to thermocouples thermistors and RTDs The TBX 1328 provides high accuracy thermocouple measurements using an onboard cold junction compensation CJC sensor To find out how to read the CJC refer to the documentation for the module in use Temperature measurements with thermistors and RTDs require excitation The TBX 1328 provides excitation connectivity when used with an SCXI 1121 Refer to the SCXI 1121 User Manual for more information on connecting thermistors and RTDs to the excitation channels Switch S1 switches the temperature sensor output between MTEMP multiplexed mode and DTEMP parallel mode modes In either mode if there are temperature variations
12. s SCXIFIIIG siiin wae 8 input channels Cold junction temperature sensor circuitry Sensor LY PC i ani R Thermistor Output ANg essenin 1 91 to 0 65 VDC from 0 to 50 C Accuracy aeoe a aA 0 5 C from 15 to 35 C 0 9 C from 0 to 15 C and 35 to 50 C Repeatability eeeeeeneees 0 2 C from 15 to 35 C Coupling eniri ieai iiiar aik DC Current receiver resistors Resistors not included Resistor sockets are provided for each channel Field wiring connectors Signal screw terminals 0 0 0 16 screw terminals 8 pairs Functional earth ground 8 screw terminals Terminal spacing 00 eee 0 5 cm 0 2 in center to center Maximum wire gauge 16 AWG Strain relief eee eee eeeeeees none Dimensions of front entrance 1 2 by 7 3 cm 0 47 by 2 87 in This specification includes the accuracy of the temperature sensor circuitry itself and the temperature difference between the thermistor and any screw terminal The temperature sensor circuitry accuracy includes manufacturing tolerances in all component values effects caused by component value temperature drift voltage divider loading and thermistor self heating 2 Tn instrumentation terminology DC coupling means that both DC and AC signals are passed TBX 1328 Installation Guide 8 ni com Mechanical DIMENSIONS issic eesis 12 7 by 7 62 by 11 16 cm 5 0 by 3 0 by 4 4 in Weight snien neninn 100 g 3 5 oz Compatibl
13. sor Circuit Diagram National Instruments Corporation 11 TBX 1328 Installation Guide In LabVIEW you can use the Convert Thermistor Reading VI in the Data Acquisition Signal Conditioning palette If you are using Measurement Studio or NI DAQ use the Thermistor_Convert function The VI takes the output voltage of the temperature sensor the reference voltage and the precision resistance and returns the thermistor temperature Alternatively you can use the following formulas T C Tg 273 15 where Tx is the temperature in degrees kelvin 1 Tk Gro ht ik ae a b InR c inR 7 J a 1 295361 x 10 3 b 2 343159 x 10 4 c 1 018703 x 10 7 Rr resistance of the thermistor in ohms y R 5 000 TEMPOUT 2 5 Vrgmpou Vrempour Output voltage of the temperature sensor T F Heo 32 where 7 F and T C are the temperature readings in degrees Fahrenheit and degrees Celsius respectively a Note Use the average of a large number of samples to obtain the most accurate reading For example sample for 1 second and average all the samples Noisy environments require more samples for greater accuracy TBX 1328 Installation Guide 12 ni com Reading the Temperature Sensor in LabVIEW Ss Notes This section does not apply to the SCXI 1126 When using virtual channels select Built in as the source of the CJC and NI DAQ will perform compensation automatically for that thermocouple channel You do not ne
14. tive compensation move the load closer to the SCXI module by using shorter cable lengths or use heavy gauge wire to connect to the TBX 1328
15. train gauge is connected at the TBX 1328 across the excitation outputs provided on the SCXI 1121 To reduce errors in the output voltage first calculate the voltage drop across the SH32 32 A cable This voltage drop results in a measurement error that National Instruments Corporation 13 TBX 1328 Installation Guide depends on the cable length and on the strain gauge value and configuration The SH32 32 A cable has a resistance Rz of 0 21 Q m Figure 6 shows a typical full bridge strain gauge circuit To determine the amount of error introduced by the cable complete the following steps 1 Calculate the total resistance R7 of the cable based on the cable length B Note Remember to include the lead resistance of both V and Vex 2 Determine the bridge resistance of the strain gauge Rs connected at the TBX 1328 TBX 1328 Installation Guide 14 ni com SCXI 1121 i AMHIGH VOLTAGE assrisai 78 o1 S N CE NATIONAL ry ee ZON R9 O N NTUMENTS C2R_ Ppremeae Lers 1996 tiga o em Roe Rt re R3 s MBA R5 R6 R7 p oo o s 00 00 00 ris A CH4 CHE J13 z B CH cH5 EX2 IS ie IH n CH6 CH3 iS KO TBX 1328 edie 250 V CAT II MAX CHANNEL TO CHANNEL Note Each sensor lead R_ has an added lead resistance
16. y that includes the TBX cable adapter 3 16 in wrench Numbers and 2 Phillips screwdrivers 1 8 in flathead screwdriver Long nose pliers Wire cutter Wire insulation stripper Sy Note You can download any NI document from ni com manuals Connecting the Signals 3 Note Refer to the Read Me First Safety and Radio Frequency Interference document before removing equipment covers or connecting or disconnecting any signal wires To connect the field signals to the TBX 1328 for use with the SCXI 1120 or SCXI 1121 follow the labeling on the TBX 1328 indicated along with the appropriate SCXI module type column as shown in Figure 1 For the SCXI 1120D SCXI 1125 and SCXI 1126 modules use the SCXI 1120 label To connect the signals complete the following steps referring to Figures 1 through 3 as necessary 1 National Instruments Corporation Remove the TBX 1328 terminal block cover by unscrewing the four captive cover screws in the cover corners These screws stay attached to the cover without falling out Connect the signal wires to the screw terminals Refer to the SCXI module user manual for examples of how to connect to field signals and loads The chassis ground terminals are connected to the SCXI 3 TBX 1328 Installation Guide chassis through the cable shield This connection is not shown in the SCXI module user manual Allow the signal wires to exit through the TBX 1328 cover opening Notes When using the SCXI
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