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Chapter 3

Signal Connections

AMUX-64T User Manual

3-10

©

 National Instruments Corporation

input range with a gain of 500 gives the best resolution. Set the jumpers on 
the MIO board for differential input, ±10 V input range.

Note

Set jumper W1 on the AMUX-64T to select the temperature sensor, and connect 
the thermocouple to CH1 and CH33. Connect a resistor between CH33 and GND 
for the bias current return path.

Set the jumpers on the MIO board for single-ended input, ±10 V input range. Set 
jumper W1 on the AMUX-64T to select the temperature sensor, and connect the 
thermocouple to CH1.

Two software compensation procedures for this example follow. 
Procedure 1 is more accurate, but procedure 2 is faster and requires less 
computation.

Procedure 1

1.

Read the voltage from the temperature sensor (channel 0). If you are 
using NI-DAQ, you can use the 

AI_Read

 and 

AI_Scale

 functions to 

do the reading. This voltage is 10 mV/°C, so the gain should be either 
1 or 10 (10 for the best resolution). Multiply the voltage by 100 to get 
the AMUX-64T temperature in degrees Celsius. For example, if the 
reading is 0.25 V, the AMUX-64T is at 25 °C.

2.

Translate the reading into the voltage for a J-type thermocouple at that 
temperature using either a look-up table or an NIST polynomial. 
Notice that the polynomials required here are the inverses of those 
given in Table 3-3. For your reading of 25 °C, you would have 
1.277 mV.

3.

Read the voltages on any thermocouple channels. If you are using 
NI-DAQ, you can use the 

AI_Read

 and 

AI_Scale

 functions to read 

each channel. For the example given, assume that you get a reading of 
9.39 mV on channel 1.

4.

Add the voltage from step 2 to the voltage measured in step 3. You then 
have:

1.277 + 9.39= 10.667 mV

5.

Translate the result into a temperature using either a look-up table or a 
polynomial such as one from Table 3-3. For example, assume that the 
reading from the J-type thermocouple is 10.667 mV. By applying the 
third formula in the Linearizing the Data section and using the 
coefficients from Table 3-3, you can calculate that the temperature 
is 198 °C.

Summary of Contents for AMUX-64T

Page 1: ...DAQ AMUX 64T User Manual Analog Multiplexer with Temperature Sensor AMUX 64T User Manual January 1999 Edition Part Number 320253C 01...

Page 2: ...36 Canada Ontario 905 785 0085 Canada Qu bec 514 694 8521 Denmark 45 76 26 00 Finland 09 725 725 11 France 01 48 14 24 24 Germany 089 741 31 30 Hong Kong 2645 3186 Israel 03 6120092 Italy 02 413091 Ja...

Page 3: ...NSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort includin...

Page 4: ...ication Software 1 3 NI DAQ Driver Software 1 3 Register Level Programming 1 6 Optional Equipment 1 7 Chapter 2 Configuration and Installation Board Configuration 2 1 Power Temperature Sensor and Shie...

Page 5: ...4 Channel Configurations 4 5 Connecting Nonreferenced or Floating Signal Sources 4 5 Differential Inputs 4 5 Single Ended Inputs 4 6 Connecting Ground Referenced Signal Sources 4 7 Differential Inputs...

Page 6: ...el 1 4 6 Figure 4 3 Normalized Frequency Response of Lowpass Filter 4 8 Figure 4 4 Lowpass Filter on Differential Channel 1 4 9 Figure 4 5 Normalized Frequency Response of Highpass Filter 4 10 Figure...

Page 7: ...Settings for Four Board Configuration 2 10 Table 3 1 Pin Mapping for I O Connectors J1 J2 and J42 3 2 Table 3 2 Thermocouple Voltage Output Extremes mV 3 6 Table 3 3 NIST Polynomial Coefficients 3 8...

Page 8: ...need to get started with your AMUX 64T describes the software programming choices and optional equipment and explains how to unpack your AMUX 64T Chapter 2 Configuration and Installation describes the...

Page 9: ...data loss or a system crash This icon to the left of bold italicized text denotes a warning which advises you of precautions to take to avoid being electrically shocked bold italic Bold italic text d...

Page 10: ...tion to help you write your application If you have a large and complicated system it is worthwhile to look through the software documentation before you configure your hardware Accessory installation...

Page 11: ...mments on our products and manuals We are interested in the applications you develop with our products and we want to help if you have problems with them To make it easy for you to contact us this man...

Page 12: ...for low cost thermocouple cold junction compensation Cold junction compensation is achieved by adding the temperature reading of the sensor to the temperature readings of thermocouples at the remainin...

Page 13: ...metal part of your computer chassis before removing the device from the package Remove the device from the package and inspect the device for loose components or any other sign of damage Notify Natio...

Page 14: ...LabWindows for DOS is for use on PCs running DOS and LabWindows CVI is for use on PCs running Windows and for Sun SPARCstations LabWindows CVI features interactive graphics a state of the art user in...

Page 15: ...DIO 24 can transfer data using interrupts or software polling With the NI DAQ Resource Manager you can simultaneously use several functions and several DAQ devices The Resource Manager prevents multip...

Page 16: ...C for Windows and Microsoft Visual C for Windows NT You can use your AMUX 64T together with other PC AT MC EISA DAQCard and DAQPad Series DAQ and SCXI hardware with NI DAQ software for PC compatibles...

Page 17: ...lways consider using NI DAQ LabVIEW or LabWindows to program your National Instruments DAQ hardware Using the NI DAQ LabVIEW or LabWindows software is easier than and as flexible as register level pro...

Page 18: ...0 5 or 1 0 m cable SH6868 shielded cable assembly with 1 2 5 or 10 m cable SH6850 shielded cable assembly with 1 2 5 or 10 m cable R6868 1 m ribbon cable assembly R6850 1 m ribbon cable assembly Rack...

Page 19: ...ch at U12 configures the AMUX 64T for single board or multiple board operation Switch SW1 selects either the internal 5 V power from the MIO board or an external 5 V power source for the AMUX 64T Jump...

Page 20: ...64T User Manual 2 2 National Instruments Corporation Figure 2 1 AMUX 64T Parts Locator Diagram 1 Serial Number 2 J1 3 W1 4 J2 5 J42 6 Temperature Sensor 7 Product Name and Assembly Number 8 U12 9 W2 1...

Page 21: ...ion Use this setting to draw 5 V power from an external supply connected to connector J41 Table 2 2 Temperature Sensor Selection Jumper Description Configuration CH0 and CH32 position Use this setting...

Page 22: ...lection Jumper Description Configuration No Connect position Use this setting to disconnect the AMUX 64T analog ground from the shield of a rack mounted chassis factory setting AIGND position Use this...

Page 23: ...Semiconductor LM 35CZ that provides a voltage output of 10 m V C with an accuracy of 1 C The sensor is jumper selected on differential input channel 0 Table 2 4 MIO Board Power Budget Board Power Allo...

Page 24: ...isolated from the rack Jumper W3 connects the shield of the 68 position connector to the rack mount kit Setting this jumper to the CABLE SHLD position connects the shield of the 68 position connector...

Page 25: ...s to different AMUX 64T boards Table 2 5 lists the description and configuration of the switches Note In all of the following dual in line package DIP switch illustrations the dark shaded end of the s...

Page 26: ...rmined by the configuration of switch U12 The switch settings for each board configuration are given in the following sections Table 2 6 Channel Ranges for Multiple AMUX 64T Boards Number of External...

Page 27: ...board has a different switch setting You assign the first board channel addresses from 0 to 63 the second board channel addresses from 64 to 127 the third board channel addresses from 128 to 191 and...

Page 28: ...ard I O connector to J42 on the AMUX 64T If you use more than one AMUX 64T you can daisy chain the boards by connecting J1 or J2 on one AMUX 64T to J1 or J2 on another AMUX 64T and so on see Figure 2...

Page 29: ...sitioning for the AMUX 64T Power On Sequence If the AMUX 64T is powered by an external power source you must turn on power to the AMUX 64T before turning on the computer Similarly you must turn off po...

Page 30: ...any way If it is damaged disconnect power and do not use the board until service trained personnel can check its safety If necessary return the board to National Instruments for service and repair to...

Page 31: ...pping for I O Connectors J1 J2 and J42 50 Pin Connector J1 and J2 Pin Numbers 68 Pin Connector J42 Pin Numbers 1 2 24 27 29 32 56 59 64 67 3 68 4 34 5 33 6 66 7 65 8 31 9 30 10 63 11 28 12 61 13 60 14...

Page 32: ...al 25 52 26 19 27 17 28 51 29 49 30 16 31 47 32 48 34 35 8 14 36 46 37 45 38 11 39 10 40 43 41 42 42 41 43 40 44 6 45 5 46 38 47 37 48 3 49 2 50 1 Table 3 1 Pin Mapping for I O Connectors J1 J2 and J4...

Page 33: ...E pin and that AIGND on the AMUX 64T is connected to the AIGND signal of the MIO board Figure 3 1 AMUX 64T Signal Routing AMUX 64T Input Signals Signals Sent to MIO Board CH0 CH1 CH2 CH3 CH4 CH5 CH6 C...

Page 34: ...either differential or single ended configurations Differential connection tends to yield the best results but single ended connection allows twice as many thermocouples to be used on each AMUX 64T T...

Page 35: ...r memory usage The polynomials are in the following form where x is the thermocouple voltage in volts T is the temperature difference between the measuring end and the AMUX 64T screw terminals in degr...

Page 36: ...written several extra multiplications will be performed to raise x to the various powers If the polynomial is instead written as follows and evaluated this way no powers are computed and execution pro...

Page 37: ...31 1 2668171E 24 c8 1 1564890E 29 1 0629823E 35 8 3823321E 29 c9 3 2447087E 41 R R S S K K 50 C to 250 C 0 02 C 250 C to 1 200 C 0 005 C 50 C to 250 C 0 02 C 250 C to 1 200 C 0 01 C 200 C to 0 C 0 04...

Page 38: ...Check with the vendor to determine the output polarity of any particular thermocouple Since thermocouples are floating signal sources you must attach a bias return resistor between the negative chann...

Page 39: ...be either 1 or 10 10 for the best resolution Multiply the voltage by 100 to get the AMUX 64T temperature in degrees Celsius For example if the reading is 0 25 V the AMUX 64T is at 25 C 2 Translate the...

Page 40: ...on temperature from step 1 to the temperature obtained in the previous step This result is the temperature at the measuring end of the thermocouple For the example given the temperature is 175 C 25 C...

Page 41: ...Sources of Error There are several major sources of error when making thermocouple measurements with the AMUX 64T and an MIO board These sources of error are compensation linearization measurement an...

Page 42: ...n on thermocouple wire errors and more specific data see Application Note 043 Measuring Temperature with Thermocouples Thermocouple Measurement Accuracies Table 3 4 lists the expected thermocouple acc...

Page 43: ...uments Corporation Other Connection Considerations Refer to the sections titled Analog Input Signal Connections and Cabling and Field Wiring in the Signal Connections chapter of the user manual that c...

Page 44: ...designated as resistors and one is designated as a capacitor The board is shipped with jumpers in two positions for each input The equivalent circuit of one input is shown in Figure 4 1 You can use th...

Page 45: ...ble 4 1 Component Positions in Each Channel Channel Positions in Figure 4 1 Differential Single Channel A B C D E F G 0 0 32 R1 R2 R3 R4 R65 R66 C3 1 1 33 R5 R6 R7 R8 R67 R68 C4 2 2 34 R9 R10 R11 R12...

Page 46: ...17 17 49 R133 R134 R135 R136 R99 R100 C38 18 18 50 R137 R138 R139 R140 R101 R102 C39 19 19 51 R141 R142 R143 R144 R103 R104 C40 20 20 52 R145 R146 R147 R148 R105 R106 C41 21 21 53 R149 R150 R151 R152...

Page 47: ...lowing applications require you to make modifications to the printed circuit board usually in the form of removing jumpers and adding components The AMUX 64T board is shipped with wire jumpers in the...

Page 48: ...an instrument or device has an isolated output that instrument or device falls into the floating signal source category Some examples of floating signal sources are outputs for the following thermoco...

Page 49: ...ed to the analog ground Therefore you should use the AMUX 64T board in its factory configuration In the factory configuration jumpers are in the two series positions E and F see Table 4 1 In this conf...

Page 50: ...n this chapter in the open component positions Single Ended Inputs When measuring ground referenced signals the external signal supplies its own reference ground point and the MIO board should not sup...

Page 51: ...malized frequency is shown in Figure 4 3 Figure 4 3 Normalized Frequency Response of Lowpass Filter When measuring low frequency signals about 4 Hz if you have 400 Hz noise on your inputs you can add...

Page 52: ...ds using 1 or better tolerance resistors in this application because differences between the resistor values degrade the common mode rejection ratio Figure 4 4 shows both the schematic and the compone...

Page 53: ...ized frequency is shown in Figure 4 5 Figure 4 5 Normalized Frequency Response of Highpass Filter When measuring high frequency signals about 50 kHz if you have 50 Hz noise on your inputs you can add...

Page 54: ...on 4 2 6 366 or about 6 4 k Therefore in this example the input channel has a 6 37 k resistor or closest standard value in its capacitor position G The closest standard 5 tolerance resistors are 6 2 k...

Page 55: ...is outside the normal input range of the DAQ board 10 V max Warning The AMUX 64T board is not designed for any input voltages greater than 42 V even if a user installed voltage divider reduces the vol...

Page 56: ...Channel 1 The gain G of this attenuator is given by the following equation 4 3 Therefore the input to the MIO board VMIO is where VSC is the voltage applied to the screw terminals of the AMUX 64T The...

Page 57: ...anual 4 14 National Instruments Corporation Example Using the values in Figure 4 7 Therefore When the MIO board is configured for 10 V inputs the board can acquire 30 V signals with this attenuator ci...

Page 58: ...contains register level programming information for the MIO board Note If you plan to use a software package such as LabWindows NI DAQ or LabVIEW with your MIO board you need not read this chapter Fu...

Page 59: ...MUX 64T scanning counter The MIO signal SCANCLK which is active during scanned data acquisition switches the input channels automatically on the AMUX 64T after each A D conversion CH0 CH1 CH2 CH3 Jump...

Page 60: ...ore an AMUX 64T channel can be selected digital I O port A must be enabled as a digital output port You can enable this port by setting the DOUTEN0 bit in the MIO Command Register 2 this bit has diffe...

Page 61: ...Table 5 1 AMUX 64T Channel Selection Channel Number Mux Gain Register MA 3 0 Digital Port A Bits ADO 1 0 0 0000 00 1 0000 01 2 0000 10 3 0000 11 4 0001 00 5 0001 01 6 0001 10 7 0001 11 28 0111 00 29...

Page 62: ...single channel This 8 bit address must be split and written to the Digital Output Register and the Mux Gain Register the Mux Mem Register in the AT MIO 16F 5 Figure 5 3 shows the mapping of the 8 bit...

Page 63: ...to load the channel address into the AMUX 64T scanning counter 3 Write to the MA 3 0 bits in the Mux Gain Register to select the four to one multiplexer on the AMUX 64T you want to address Now follow...

Page 64: ...nput in the sequence When the MIO board is used alone a single level multiplexer switches the 16 input channels to the analog to digital converter ADC A two level multiplexer must be controlled when a...

Page 65: ...64T channels must be scanned for every MIO board input channel For example channels 0 through 3 on AMUX 64T board A and channels 64 through 67 on AMUX 64T board B are multiplexed together into MIO bo...

Page 66: ...2 3 CH0 MIO Board Two Board Configuration Board B 4 5 6 7 CH0 CH1 CH2 CH3 Board A Scanning Order 0 1 2 3 CH0 MIO Board CH0 64 CH1 65 CH2 66 CH3 67 8 9 10 11 CH0 CH1 CH2 CH3 Board A Four Board Configur...

Page 67: ...r for Each MIO Board Input Channel MIO Board AMUX 64T Channels One Board Two Boards Four Boards Board A Board A Board B Board A Board B Board C Board D 0 0 3 0 3 64 67 0 3 64 67 128 131 192 195 1 4 7...

Page 68: ...iguration The scanning order becomes complex only when more than one AMUX 64T board is used During interval scanning the number of channels scanned during an interval is four times the channel scan se...

Page 69: ...the Counter 1 mode value Write FF09 to the Am9513 Command Register to select the Counter 1 Load Register Write the divide down value to the Am9513 Data Register to load counter 4 The divide down valu...

Page 70: ...umber of channels Single board 64 single ended or 32 differential Two boards 128 single ended or 64 differential Four boards connected 256 single ended or 128 differential Input signal ranges Differen...

Page 71: ...O 16E 2 AT MIO 16E 10 NB MIO 16 FS 0 to FS FS 0 to FS FS 0 to FS 5 5 3 9 8 1 5 3 9 8 14 12 2 5 3 9 8 5 5 3 9 8 10 6 4 9 8 20 15 20 6 5 10 9 50 7 6 11 10 100 9 8 12 11 20 20 500 50 50 Two AMUX 64T Boar...

Page 72: ...r external power 5 VDC 5 150 mA typ Physical Dimensions 12 75 by 3 80 in 32 43 by 9 65 cm I O connector Two 50 pin male ribbon cable connectors one 68 pin male shielded or ribbon cable connector 78 sc...

Page 73: ...Appendix A Specifications AMUX 64T User Manual A 4 National Instruments Corporation Environment Operating temperature 0 to 70 C Storage temperature 55 to 150 C Relative humidity 5 to 90 noncondensing...

Page 74: ...es not answer your questions we offer fax and telephone support through our technical support centers which are staffed by applications engineers Electronic Services Bulletin Board Support National In...

Page 75: ...office in your country contact the source from which you purchased your software to obtain support Country Telephone Fax Australia 03 9879 5166 03 9879 6277 Austria 0662 45 79 90 0 0662 45 79 90 19 Be...

Page 76: ...___ Instruments used _________________________________________________________________ _______________________________________________________________________________ National Instruments hardware pro...

Page 77: ...________________________________________________________ National Instruments software ______________________________________________________ Other boards in system ___________________________________...

Page 78: ..._______ _______________________________________________________________________________ _______________________________________________________________________________ ________________________________...

Page 79: ...9 micro 10 6 m milli 10 3 k kilo 103 M mega 106 Numbers Symbols degrees greater than greater than or equal to less than negative of or minus ohms percent plus or minus positive of or plus 5 V 5 Volts...

Page 80: ...s cm centimeters CMOS complementary metallic oxide semiconductor CNTINT Counter Interrupt signal D D A digital to analog D A Data Address signal DAC digital to analog converter DAC OUTPUT UPDATE DAC o...

Page 81: ...ased programmable read only memory EPP Enhanced Parallel Port EXTCONV External Convert signal EXTTRIG External Trigger signal EXTUPDATE External Update signal F ft feet G GATB 0 2 Counter B0 B1 B2 Gat...

Page 82: ...t significant bit N NRSE nonreferenced single ended O OBF Output Buffer Full signal OUTB0 OUTB1 Counter B0 B1 Output signals P PA PB PC 0 7 Port A B or C 0 through 7 signals POSTTRIG Posttrigger mode...

Page 83: ...l SERDATOUT Serial Data Out signal SLOT0SEL Slot 0 Select signal SPICLK Serial Peripheral Interface Clock signal SS Slot select signal STB Strobe Input signal T TTL transistor transistor logic typ typ...

Page 84: ...Glossary AMUX 64T User Manual G 6 National Instruments Corporation Vrms volts root mean square Vs signal source W W watts WRT Write signal...

Page 85: ...ifications A 1 onboard equivalent circuit figure 4 2 attenuators voltage dividers building 4 12 to 4 14 attenuators for use with differential inputs figure 4 13 input voltage greater than 42 V warning...

Page 86: ...on 2 6 single board configuration factory settings 2 9 jumper settings table 2 7 temperature sensor selection jumper settings table 2 3 supplementary information 2 5 to 2 6 two board configuration ins...

Page 87: ...thermocouple data 3 6 to 3 9 lowpass filters building 4 8 to 4 9 lowpass filter on differential channel 1 figure 4 9 normalized frequency response figure 4 8 to 4 9 M manual See documentation MIO boa...

Page 88: ...ch channel table 4 2 to 4 4 onboard equivalent circuit figure 4 2 application notes 4 4 to 4 14 building attenuators voltage dividers 4 12 to 4 14 attenuators for use with differential inputs figure 4...

Page 89: ...or A 3 environment A 4 physical A 3 power requirement A 3 switch settings See configuration T technical support B 1 to B 2 telephone and fax support numbers B 2 temperature sensor selection jumper set...

Page 90: ...T User Manual I 6 National Instruments Corporation thermocouple output extremes table 3 6 using more than one AMUX 64T 3 12 U unpacking the AMUX 64T 1 2 V voltage dividers See attenuators voltage divi...

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