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SC-2070 Board

Chapter 2

SC-207X Series User Manual

2-16

© National Instruments Corporation

Working with Thermocouples

One of the most frequently used temperature transducers is the thermocouple. A thermocouple is
created when two dissimilar metals are brought in contact, and the contact produces a small voltage as
a function of temperature. In most measurement situations, a thermocouple is placed where the
temperature is to be measured; then two wires, consisting of the same type of metal as each side of the
thermocouple, are run back to a termination panel such as the SC-2070. Additional dissimilar
junctions are formed where these wires contact the screw terminals, and each of these junctions
generates its own temperature-dependent voltage. Other temperature-dependent voltages are generated
at ribbon cable junctions and solder joints. However, effects of these junctions are negligible and tend
to cancel in most cases. The voltage measured by the DAQ board is the sum of the voltages of all
dissimilar metal junctions in the circuit, not just the thermocouple junction used to measure
temperature.

You only need to know the temperature of the screw terminal junctions to compensate for all dissimilar
metal junctions in a system with constant temperature (Thermocouple Law of Intermediate Metals).
Therefore, if you know the temperature at the screw terminals, you can easily calculate the temperature
at the point of interest from the voltage measured. A National Semiconductor LM-35CZ is used on the
SC-2070 board to determine the temperature of the screw terminals. The dissimilar metal junctions at
the screw terminals are also referred to as the cold junction. The process of using the known
temperature at that point to find the temperature at the unknown point is called cold-junction
compensation (CJC).

Thermocouples are usually more desirable than direct-reading sensors for several reasons.
Thermocouples are more rugged than most other sensors and can tolerate several hundred degree
temperatures without degradation. Semiconductor sensors, the easiest to use, usually cannot be used
above 70

°

C. Thermocouples are inexpensive and physically small, so they can track temperature

changes rapidly.

Thermocouple output voltages are very low, on the order of 50

µ

V/

°

C. The temperature coefficient

changes with temperature, resulting in a nonlinear curve. The temperature can be determined from
tables available from thermocouple vendors or calculated from polynomial equations such as those
given in the next section.

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Содержание SC-207 Series

Страница 1: ... Copyright 1991 1995 National Instruments Corporation All Rights Reserved SC 207X Series User Manual General Purpose Termination Breadboards November 1995 Edition Part Number 371173A 01 ...

Страница 2: ...Belgium 02 757 00 20 Canada Ontario 519 622 9310 Canada Québec 514 694 8521 Denmark 45 76 26 00 Finland 90 527 2321 France 1 48 14 24 24 Germany 089 741 31 30 Hong Kong 2645 3186 Italy 02 48301892 Japan 03 5472 2970 Korea 02 596 7456 Mexico 95 800 010 0793 Netherlands 0348 433466 Norway 32 84 84 00 Singapore 2265886 Spain 91 640 0085 Sweden 08 730 49 70 Switzerland 056 200 51 51 Taiwan 02 377 1200...

Страница 3: ...RPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of Nation...

Страница 4: ...r or application designer Any use or application of National Instruments products for or involving medical or clinical treatment must be performed by properly trained and qualified medical personnel and all traditional medical safeguards equipment and procedures that are appropriate in the particular situation to prevent serious injury or death should always continue to be used when National Instr...

Страница 5: ...d Timing Signals 2 4 Board to Board Cabling 2 5 Mounting 2 6 Applications 2 6 Soldering and Desoldering on the SC 2070 Board 2 7 Channel Configurations 2 7 Connecting Nonreferenced or Floating Signal Sources 2 7 Differential Inputs 2 7 Single Ended Inputs 2 8 Connecting Ground Referenced Signal Sources 2 9 Differential Inputs 2 9 Single Ended Inputs 2 9 Building Lowpass Filters 2 10 Building Highp...

Страница 6: ... the SC 2071 Board 3 7 Connecting Floating Signal Sources 3 8 Connecting Grounded Signal Sources 3 8 Building Lowpass Filters 3 8 Building Highpass Filters 3 10 Building Attenuators Voltage Dividers 3 12 Working with Thermocouples 3 14 Using the SC 2071 Board for Thermocouple Measurements 3 15 Input Filtering and Broken Thermocouple Detection Optional 3 15 Selecting the Gain and Input Ranges 3 16 ...

Страница 7: ...Cable Adapter Boards 5 2 Installing the BNC 2081 Analog Breakout Board 5 3 Rack Mounting 5 3 External Power Connection If Necessary 5 4 SC 207X Series Board Connection 5 7 Signal Connections 5 8 Ribbon Cable Connectors 5 8 Screw Terminal Connections for the SC 2070 and the SC 2071 5 8 Screw Terminal Connections for the SC 2072 5 9 Rack Mount Chassis Cover Attachment 5 9 Appendix A Specifications A...

Страница 8: ...cator Diagram 3 2 Figure 3 2 Onboard Equivalent Circuit 3 3 Figure 3 3 W1 Jumper Settings 3 4 Figure 3 4 W2 Jumper Settings 3 4 Figure 3 5 Direct Connection between a Lab 1200 Device and the SC 2071 Board 3 5 Figure 3 6 Daisy chaining a Lab 1200 Device to a BNC 2081 3 6 Figure 3 7 Connection between a Lab 1200 Device and the SC 2071 Board via the SC 2053 Board 3 6 Figure 3 8 Normalized Frequency R...

Страница 9: ...ficients 2 21 Table 2 5 Thermocouple Measurement Accuracies 2 25 Table 3 1 Component Positions in Each Channel 3 3 Table 3 2 DAQ Devices Used with the SC 2071 Board 3 5 Table 3 3 Thermocouple Voltage Output Extremes mV 3 17 Table 3 4 NBS Polynomial Coefficients 3 18 Table 3 5 Thermocouple Measurement Accuracies 3 21 Table 4 1 Switch S2 Settings for National Instruments DAQ Devices 4 4 Table 5 1 Am...

Страница 10: ...ter 2 SC 2070 Board describes the SC 2070 board in detail including function compatibility connection mounting and applications This chapter also discusses working with thermocouples Chapter 3 SC 2071 Board describes the SC 2071 board in detail including function compatibility connection mounting and applications This chapter also discusses working with thermocouples Chapter 4 SC 2072 Board descri...

Страница 11: ...96 boards DIO 24 DIO 24 refers to the NB DIO 24 MC DIO 24 and PC DIO 24 boards DIO 32F DIO 32F refers to the NB DIO 32F MC DIO 32F and AT DIO 32F boards Lab 1200 Series Lab 1200 Series refers to the Lab LC Lab NB Lab PC and Lab PC boards and the DAQCard 1200 DAQPad 1200 and PCI 1200 devices MIO 16 MIO 16 refers to the NB MIO 16 NB MIO 16X MC MIO 16 AT MIO 16 AT MIO 16D AT MIO 16F 5 and AT MIO 16X ...

Страница 12: ... Types Based on the ITS 90 National Institute of Standards and Technology Gaithersburg MD 20899 Customer Communication National Instruments wants to receive your comments 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 manual contains comment and configurati...

Страница 13: ...d temperature sensor for cold junction compensation The temperature sensor can be disconnected to make all eight differential or 16 single ended analog input channels available on the board The boards have silkscreened component locations for resistors and capacitors for building single pole highpass and lowpass filters voltage dividers and broken thermocouple detectors The SC 2070 and SC 2071 boa...

Страница 14: ...AT MIO 16 AT MIO 16D1 AT MIO 16F 5 AT MIO 16X PC DIO 24 PC DIO 96 PC LPM 16 PC TIO 10 Lab LC2 Lab NB Lab PC DAQCard 1200 DAQPad 1200 PCI 1200 DAQCard 700 DAQCard DIO 24 PC OPDIO 16 1 Requires an NB5 cable available separately 3 Requires a PR50 50F cable available separately 2 Requires an NB10 cable available separately All the signals from the DAQ board both analog and digital are made available a...

Страница 15: ......

Страница 16: ... Type NB10 cable Rack mount chassis kit with acrylic plastic cover single or double height Rack mount chassis kit with metal wraparound cover single or double height SSR Series eight channel backplane with 0 4 m cable for SC 2050 Series SC 2060 and 26 conductor cable 0 2 or 0 4 m SC 2061 and 26 conductor cable 0 2 or 0 4 m SC 2062 and 26 conductor cable 0 2 or 0 4 m SC 2050 and 50 conductor cable ...

Страница 17: ...ling the board take the following precautions Ground yourself via a grounding strap or by holding a grounded object Touch the antistatic package to a metal part of your computer chassis before removing the board from the package Remove the board from the package and inspect the board for loose components or any other sign of damage Notify National Instruments if the board appears damaged in any wa...

Страница 18: ...Series and PC XT AT and compatible AT Series computers The SC 2070 board has screw terminalsfor all DAQ board signals With these terminals the board easily connects to the analog digital timing and trigger signals The SC 2070 has an onboard temperature sensor that can be optionally jumpered to differential channel 0 for thermocouple cold junction compensation With open component positions in the i...

Страница 19: ...or signal conditioning components Six of these positions are 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 2 2 The board can be used when the MIO 16 board is configured for both 16 single ended inputs and eight differential inputs For thermocouple and other low le...

Страница 20: ...d in the E and F positions of the input network see Figure 2 2 These jumpers can be easily removed to build analog input signal conditioning circuits Several applications showing the use of these open component positions are discussed in Applications later in this chapter Temperature Sensor The SC 2070 board is equipped with an onboard temperature sensor for use with thermocouple cold junction com...

Страница 21: ...cted by an 800 mA fuse If the red power LED does not light when the DAQ board is powered on check both the 800 mA fuse on the SC 2070 board and the output fuse if any on the MIO 16 board See Chapter 5 Installation and Connections for information on connecting power Digital and Timing Signals All of the signals from the MIO 16 board are made available at screw terminals on the SC 2070 board Because...

Страница 22: ...4F 5 board the 50 conductor cable is replaced with a type NB5 100 conductor ribbon cable The NB5 cable terminates with two 50 pin connectors one of which may be connected to the SC 2070 board MIO 16 SC 2070 50 Pin I O Connectors 50 Conductor cable Figure 2 5 Direct Connection between an MIO 16 Board and the SC 2070 Board If any signal conditioning of the digital I O ports with the National Instrum...

Страница 23: ...optional rack mount chassis which can be fitted with a flat acrylic plastic cover When the SC 2070 board is mounted in the chassis the board can be grounded to its metal standoffs and therefore to the rack For more information see Chapter 5 Installation and Connections Applications The open component positions on the SC 2070 board make adding signal conditioning components to the analog input sign...

Страница 24: ...ment 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 thermocouples transformers battery powered devices optical isolators and isolation amplifiers The ground reference of a floating source must be tied to the ground of the DAQ board to establish a local or onboard reference for the si...

Страница 25: ...d reference Therefore configure the MIO 16 for referenced single ended input In this configuration the negative input of the MIO 16 instrumentation amplifier is tied to the analog ground Therefore use the SC 2070 board in its factory configuration In the factory configuration jumpers are in the two series positions E and F see Table 2 1 In this configuration all of the signal grounds should be tie...

Страница 26: ... Lowpass Filters Building Highpass Filters and Building Attenuators later in this chapter can be built 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 16 should not supply one Therefore configure the MIO 16 board for nonreferenced single ended input mode In this configuration all of...

Страница 27: ...also attenuates but by only 3 dB Do not neglect any potential attenuation of signals of interest by this low order filter You must also choose the filter component values The resistance or the capacitance can be selected arbitrarily one value determines the other Picking the capacitor first and letting its value determine the resistance required is preferable because more standard resistor values ...

Страница 28: ...or single ended inputs Therefore if the MIO 16 board is configured for single ended inputs lowpass filters must be built on the custom breadboard area Channel Channel Input Schematic To Input Multiplexer E F G 1 µF Channel 1 Channel 9 R11 R8 R7 C3 R10 R12 in in Component Positions R9 1 µF 1 µF Capacitor 19 8 kΩ 19 8 kΩ 19 8 kΩ Resistor 19 8 kΩ 19 8 kΩ Figure 2 9 Lowpass Filter on Differential Chan...

Страница 29: ... 50 kHz signal also attenuates but by only 3 dB Do not neglect any potential attenuation of signals of interest if you add a low order filter You must also choose the filter component values The resistance or the capacitance can be selected arbitrarily one value determines the other Picking the capacitor first and letting its value determine the resistance required is preferable because more stand...

Страница 30: ...ause capacitors are in the series input paths Capacitors have poorer tolerances than resistors and matching of the input impedances is crucial for good common mode rejection The SC 2070 board open component locations do not facilitate RC highpass filters with the MIO 16 board configured for single ended inputs Therefore if the MIO 16 board is configured for single ended inputs highpass filters mus...

Страница 31: ... V even if a user installed voltage divider reduces the voltage to within the input range of the DAQ board Input voltages greater than 42 V can result in damage to the SC 2070 board any and all boards connected to it and the host computer Overvoltage can also cause an electric shock hazard for the operator National Instruments is NOT liable for damage or injury resulting from such misuse A three r...

Страница 32: ...R9 10 kΩ C3 10 kΩ Resistor Channel Input Schematic E G 10 kΩ Channel F 10 kΩ 10 kΩ F E G RE R G R F V SC VMIO To MIO 16 Figure 2 12 Attenuator for Use with Differential Inputs Example Using the values in Figure 2 12 G 10 kΩ 10 kΩ 10 kΩ 10 kΩ 1 3 Therefore VMIO 1 3 VSC When the MIO 16 is configured for 10 V inputs the board can acquire 30 V signals with this attenuator circuit ...

Страница 33: ...rminal junctions to compensate for all dissimilar metal junctions in a system with constant temperature Thermocouple Law of Intermediate Metals Therefore if you know the temperature at the screw terminals you can easily calculate the temperature at the point of interest from the voltage measured A National Semiconductor LM 35CZ is used on the SC 2070 board to determine the temperature of the screw...

Страница 34: ...being read keep the SC 2070 board away from drafts or other temperature gradients such as those caused by heaters radiators fans and very warm equipment Input Filtering and Broken Thermocouple Detection Optional To reduce noise a lowpass filter can be connected Refer to Building Lowpass Filters earlier in this chapter for an explanation of how to design these filters Broken thermocouple detection ...

Страница 35: ...it with Open Thermocouple Detect and Lowpass Noise Filter Selecting the Gain and Input Ranges Because thermocouple output voltages are very low a gain of 500 or 100 is usually necessary for best resolution The input range on the MIO 16 should be set to 5 V to improve resolution These settings can be used in all but a few cases such as a fairly high output thermocouple type that is being used at el...

Страница 36: ... For this reason the temperature from thermocouple voltages must either be approximated by polynomials or matched against a look up table The polynomial approach is easier to use but it trades measurement time for memory usage The polynomials are in the form T a0 a1x a2x2 a nxn Formula 2 4 where x is the thermocouple voltage in volts T is the temperature difference between the measuring end and th...

Страница 37: ...17501E 17 3 94078E 14 a8 9 19278E 12 6 33708E 13 8 03104E 19 1 56105E 19 a9 2 06132E 13 1 69535E 20 1 The accuracies shown apply only to the polynomial and do not take into consideration errors introduced by the SC 2070 board the MIO 16 board or the thermocouple itself These polynomials are accurate only within the temperature ranges specified Also all terms must be included to achieve the specifi...

Страница 38: ...can be selected In this case the 10 V input range with a gain of 500 gives the best resolution Set the jumpers on the AT MIO 16L for differential input 10 V input range Jumper W1 on the SC 2070 board is set to select the temperature sensor as shown in Figure 2 3 To connect the thermocouple to differential channel 1 connect one lead to the CH1 terminal and the other to the CH9 terminal Notice that ...

Страница 39: ... input range with a gain of 500 gives the best resolution Set the jumpers on the AT MIO 16L for single ended input 10 V input range Jumper W1 on the SC 2070 board is set to select the temperature sensor as shown in Figure 2 3 To connect the thermocouple to single ended channel 1 connect the positive thermocouple lead to channel 1 and the negative thermocouple lead to AIGND For this example you do ...

Страница 40: ... of a thermocouple is 32 µV C this measurement error adds 0 5 C of uncertainty to the measurement For best results use a well calibrated MIO 16 board so that offsets can be neglected Offset error can be eliminated however by grounding one channel on the SC 2070 board and measuring the voltage This value the offset of the MIO 16 can then be subtracted in software from all other readings Thermocoupl...

Страница 41: ...tion Table 2 5 Thermocouple Measurement Accuracies Type Gain J K E T S R 100 2 7 C 3 7 C 2 9 C 3 6 C 9 8 C 8 5 C 500 1 4 C 2 1 C 1 8 C 1 9 C 3 6 C 2 9 C Additional Signal Connection Information For more information about signal connections see Chapter 2 in your MIO 16 board user manual ...

Страница 42: ...d has screw terminals for eight single ended input channels Open component positions at each analog input facilitate the addition of user selected signal conditioning The SC 2071 board has an onboard temperature sensor that can be optionally jumpered to channel 0 for thermocouple cold junction compensation With open component positions in the input paths you can insert user supplied resistors and ...

Страница 43: ...arts Locator Diagram Analog Input Each differential analog input has four open positions for signal conditioning components All signal conditioning components are designated as resistors but capacitors can be inserted for the construction of RC filters The board is shipped with wire jumpers in one position for each input The equivalent circuit of one input is shown in Figure 3 2 For specific appli...

Страница 44: ... the circuit shown in Figure 3 2 Table 3 1 Component Positions in Each Channel Position in Figure 3 2 Channel A B C D 0 R1 R3 R2 R4 1 R5 R7 R6 R8 2 R9 R11 R10 R12 3 R13 R15 R14 R16 4 R17 R19 R18 R20 5 R21 R23 R22 R24 6 R25 R27 R26 R28 7 R29 R31 R30 R32 When the board is shipped a jumper is inserted in the C position of the input network You can easily remove the jumper to build analog input signal...

Страница 45: ...ws the positions for jumper W1 W1 W1 a Channel 0 Selected b Temperature Sensor Selected Temp CH0 Temp CH0 Figure 3 3 W1 Jumper Settings Shield Ground Jumper W2 is used to connect digital ground DGND to a grounded metal case This option is useful only if the SC 2071 board is on metal standoffs and mounted in a grounded metal case You can select shield grounding to reduce noise Figure 3 4 shows the ...

Страница 46: ... the DAQ devices listed in Table 3 2 Table 3 2 DAQ Devices Used with the SC 2071 Board Lab 1200 Device PC XT and Macintosh SC 2071 Board Lab LC 1 Lab NB Lab PC Lab PC DAQCard 1200 2 DAQPad 1200 PCI 1200 1 Requires an NB10 cable available separately 2 Requires a PR50 50F cable available separately The SC 2071 board has two functionally equivalent 50 pin I O connectors Connect one connector directly...

Страница 47: ... with the National Instruments SC 206X Series boards the SC 2053 cable adapter board must be used with the Lab NB or Lab PC Figure 3 7 shows a connection using the SC 2053 cable adapter board SC 2053 SC 206X Series SC 206X Series SC 206X Series Port B Port A Port C SC 2071 Digital I O 50 Conductor Cable Lab 1200 Device Figure 3 7 Connection between a Lab 1200 device and the SC 2071 Board via the S...

Страница 48: ...and Connections Mounting The SC 2071 board is equipped with metal standoffs so the board can be placed on a workbench near the host computer You can use an optional rack mount chassis which can be fitted with a flat acrylic plastic cover When the SC 2071 board is mounted in the chassis the board can be grounded to its metal standoffs and therefore to the rack For more information see Chapter 5 Ins...

Страница 49: ... ground point with respect to the DAQ device assuming the host computer is plugged into the same power system Nonisolated outputs of instruments and devices that plug into the building power system fall into this category In the case of grounded signal sources connected to the single ended inputs of the SC 2071 board a small DC error can be measured because of differences between the ground potent...

Страница 50: ...low order filter You must also choose the filter component values The resistance or the capacitance can be selected arbitrarily one value determines the other Picking the capacitor first and letting its value determine the resistance required is preferable because more standard resistor values are available If a capacitance of 1 µF is available then the resistance is by substitution into Formula 3...

Страница 51: ...n easily install simple RC highpass filters in the SC 2071 board on any input channel The filters are useful for accurate high frequency measurement and low frequency noise rejection By substituting resistance and capacitance values into the following formula you can calculate a simple one pole RC filter to have a 3 dB point cutoff frequency fc 1 2πRC Formula 3 2 The response rolls off at a rate o...

Страница 52: ... the filter component values The resistance or the capacitance can be selected arbitrarily one value determines the other Picking the capacitor first and letting its value determine the resistance required is preferable because more standard resistor values are available If a 0 001 µF capacitor is available the resistance is by substitution into Formula 3 2 7958 Ω or about 8 0 kΩ Therefore in this...

Страница 53: ...e SC 2071 board Attenuators can be used to reduce a signal that is outside the normal input range of the DAQ device 10 V maximum Warning The SC 2071 board is not designed for any input voltages greater than 42 V even if a user installed voltage divider reduces the voltage to within the input range of the DAQ device Input voltages greater than 42 V can result in damage to the SC 2071 board any and ...

Страница 54: ...n G of this attenuator is given by the following formula G RD RC RD Formula 3 3 Therefore the input to the Lab 1200 device VLab is VLab VSC G where VSC is the voltage applied to the screw terminals of the SC 2071 board The accuracy of this gain equation depends on the tolerances of the resistors used 10 kΩ 10 kΩ Channel 1 AIGND R5 R7 Component Positions 10 kΩ Resistor R8 10 kΩ D R6 10 kΩ C R C RD ...

Страница 55: ...couple junction used to measure temperature Only the temperature of the screw terminal junctions must be known to compensate for all dissimilar metal junctions in a system with constant temperature Thermocouple Law of Intermediate Metals Therefore if you know the temperature at the screw terminals you can easily calculate the temperature at the point of interest from the voltage measured A Nationa...

Страница 56: ...ns and warm equipment Input Filtering and Broken Thermocouple Detection Optional To reduce noise you can connect a lowpass filter Refer to Building Lowpass Filters earlier in this chapter for an explanation of how to design these filters Broken thermocouple detection circuitry is built by connecting a high value resistor between the positive input and 5 V The value of this resistor is relatively u...

Страница 57: ...ltages are very low a gain of 100 is usually necessary for best resolution The input range on the Lab 1200 device should usually be set to 5 V to improve resolution These settings can be used in all but a few cases such as a fairly high output thermocouple type used at elevated temperatures Table 3 3 lists the voltage extremes from several popular thermocouple types Use this Table as a guide for d...

Страница 58: ...rmocouples For this reason the temperature from thermocouple voltages must either be approximated by polynomials or matched against a look up table The polynomial approach is easier to use but it trades measurement time for memory usage The polynomials are in the form T a0 a1x a2x2 a nxn Formula 3 4 where x is the thermocouple voltage in volts T is the temperature difference between the measuring ...

Страница 59: ... are accurate only within the temperature ranges specified Also all terms must be included to achieve the specified accuracy To avoid the long computation time required for these high order polynomials you can subdivide the operating range of a thermocouple into several smaller ranges Each of the smaller ranges can then be approximated by a much lower order polynomial such as the polynomial in For...

Страница 60: ...voltage on channel 0 This voltage is 10 mV C so the gain should be either 1 or 10 for this reading 10 for the best resolution Multiply the voltage by 100 to get the SC 2071 board temperature in degrees Celsius For example if the reading is 0 25 V the SC 2071 board is at 25 C 2 Read the voltage on analog input channel 1 using a gain of 100 If you are using an NI DAQ software package you can use the...

Страница 61: ...asurement For best results use a well calibrated Lab 1200 device so that offsets can be neglected Offset error can be eliminated however by grounding one channel on the SC 2071 board and measuring it This value is the offset of the Lab 1200 device and it can then be subtracted in software from all other readings Finally thermocouple wire error is the result of inconsistencies in the thermocouple m...

Страница 62: ...X Series User Manual Table 3 5 Thermocouple Measurement Accuracies Type Gain J K E T S R 100 2 7 C 3 7 C 2 9 C 3 6 C 9 8 C 8 5 C Additional Signal Connection Information For more information about signal connection refer to Chapter 2 in your Lab 1200 device user manual ...

Страница 63: ...as screw terminals for all 50 signals present on the I O cable These terminals can be used for easy connection to the analog digital timing and trigger signals from the expansion board In addition the SC 2072 board has one set of 12 terminals that can be used for connection of 12 external signals For digital power connections one set of three terminals can be used to connect digital power and grou...

Страница 64: ...lock Terminals Connector J5 6 Switch S2 2 Screw Block Terminals for Analog Power Connector J4 7 External Power Screw Block Terminals Connector J3 3 Screw Block Terminals for I O Connector Signals Connector J3 8 Switch S1 4 50 pin I O Connector 9 General Purpose Breadboard Area 5 Fuses Figure 4 1 SC 2072 Board Parts Locator Diagram ...

Страница 65: ...2 position screw terminal block J5 can be used to connect external signals to the breadboard area without connecting them to the I O cable simultaneously A line of solder holes adjacent to both J3 and J5 can be used to connect the screw terminals to the breadboard area If you rotate the SC 2072 board so that the label J3 is in the top left corner the connection holes are to the right of J3 The eve...

Страница 66: ...l block is connected to the local power and ground lines If you set the switch to the internal supply labeled INT the switch S2 is responsible for selecting the power inputs from the I O cable Switch S2 is a three position switch that configures the SC 2072 to connect to pins 49 5 V and 50 DGND in position A to no I O pins in position B and to pins 33 DGND and 34 5 V in position C Table 4 1 shows ...

Страница 67: ...al power source to supply power for your analog circuitry the DC to DC converter converts the 5 V digital power supply into 15 V and 15 V therefore supplying a convenient power source for your analog circuitry Warning If you accidentally short the terminals at J4 or otherwise connect the outputs from the DC to DC converter together damage to the converter and your breadboarded circuitry can occur ...

Страница 68: ...ure 4 4 shows a connection using the SC 2051 cable adapter board DIO 24 SC 2051 Digital I O SC 2072 SC 206X Series or 8 channel SSR 26 Conductor Cable 50 Conductor Cable Figure 4 4 Connection between a DIO 24 Board and the SC 2072 Board via the SC 2051 Board Warning Do not connect the SC 2072 board to any board other than a National Instruments DAQ device or a National Instruments SC 205X Series c...

Страница 69: ...hich can be fitted with a flat acrylic plastic cover For more information see Chapter 5 Installation and Connections Soldering and Desoldering on the SC 2072 Board Use a low wattage soldering iron 20 to 30 W when soldering to the board To desolder on the SC 2072 vacuum type tools work best Use care when desoldering to avoid damaging component pads Only use rosin core electronic grade solder Acid c...

Страница 70: ...red for the analog inputs and install the necessary components into the open component positions If no signal conditioning is needed on an input then the factory installed jumpers on the SC 2070 or jumper on the SC 2071 must be in place 2 Check that jumpers W1 and W2 are set correctly for the current application 3 Mount the SC 207X Series board into a 19 in rack optional 4 Connect the SC 207X Seri...

Страница 71: ... host computer off before making any connections 1 Mount the SC 2072 board into a 19 in rack optional 2 Connect the SC 2072 board to the DAQ device using a 50 pin ribbon cable If an SC 205X Series board is used with the SC 2072 board install and mount the SC 205X Series board as instructed in the SC 205X Series User Manual then connect the SC 2072 board to the SC 205X Series board using the 50 pin...

Страница 72: ...gnal conditioning board Mount your SC 207X Series board on the left or right side of the 19 in rack mount The SC 207X Series board occupies two of the three mounting positions shown in Figure 5 1 Left Hand Mounting Position Middle Mounting Position Right Hand Mounting Position Figure 5 1 Mounting Locations for SC 207X Series Boards Mount the SC 207X Series board in the chassis by removing the scre...

Страница 73: ...AQ devices need to be stacked double height mounting within one rack mount chassis is possible Because only one SC 207X Series board can be used with each DAQ device this situation occurs only if two or more DAQ devices are being used You need a hardware kit for double height mounting see Optional Equipment in Chapter 1 consisting of two brackets that are installed in the rack mount A second row o...

Страница 74: ... from an external 5 VDC power supply An external supply can be necessary in the following situations A particularly high current circuit has been constructed on the general purpose breadboarding area The power requirements for equipment connected to the computer s power supply exceed the rating for that supply To connect the external power supply the power supply must be turned off to the SC 2070 ...

Страница 75: ...1200 0 4 A PCI 1200 1 5 A 0 43 A 1 A2 PC DIO 24 Not Specified1 0 16 A 1 A2 PC DIO 96 Not Specified1 0 45 A 1 A2 PC LPM 16 Not Specified1 0 13 A 1 A2 PC TIO 10 Not Specified1 0 6 A 1 A2 MC DIO 24 1 6 A 0 8 A 0 8 A MC DIO 32F 1 6 A 1 4 A 0 A3 MC MIO 16 1 6 A 1 4 A 0 2 A Lab LC 0 8 A 0 25 A 0 5 A Lab NB 2 0 A 0 8 A 1 A2 NB DIO 24 2 0 A 0 8 A 1 A2 NB DIO 32F 2 0 A 1 6 A 0 A3 NB MIO 16 2 0 A 1 5 A 0 5 ...

Страница 76: ...eries SC 206X Series Port B Port A Port C SC 2071 Digital I O or 50 Conductor Cable 50 Conductor Cable 50 Conductor Cable 50 Conductor Cable BNC 2081 Lab 1200 Device Lab 1200 Device Figure 5 4 Connections Between DAQ Devices and SC 205X Series Boards and Between SC 205X Series Boards and SC 2070 and SC 2071 Boards A 50 pin ribbon cable connects your SC 207X Series board to either an SC 205X Series...

Страница 77: ...must attach to the host DAQ device The other connection can attach to the SC 2072 board Warning Do not attempt to connect an SC 207X Series board to any connector for which it is not designed Such connections can result in damage to any or all of the boards connected to the SC 207X Series board to the host computer and to the SC 207X Series boards themselves National Instruments is NOT liable for ...

Страница 78: ...o the host computer and to the SC 207X Series boards Overvoltage conditions also can present a shock hazard to you National Instruments is NOT liable for any damages or injuries resulting from incorrect signal connections Rack Mount Chassis Cover Attachment The optional 19 in rack mount accessory includes a flat acrylic plastic cover that can be installed using the four screws included in the kit ...

Страница 79: ...he inputs of the DAQ boards Breadboarding Area SC 2070 and SC 2071 10 2 by 3 8 cm 4 0 by 1 5 in SC 2072 10 9 by 7 6 cm 4 3 by 3 0 in Feedthrough size 0 09 cm 0 0351 in diameter on 0 25 cm 0 1 in center spacing Features Eight undedicated screw terminal connections 40 feedthroughs connected to 5 VDC 40 feedthroughs connected to ground Voltage available 5 V and DGND on two bus strips Power Requiremen...

Страница 80: ... Physical Dimensions including standoffs 20 1 by 12 5 by 4 6 cm 7 9 by 4 9 by 1 8 in Signal connections 54 screw terminals I O connector One 50 pin male ribbon cable connector Environment Operating temperature 0 to 70 C Storage temperature 55 to 110 C Relative humidity 5 to 90 noncondensing ...

Страница 81: ...nearest branch office You may fax questions to us at any time Corporate Headquarters 512 795 8248 Technical support fax 800 328 2203 512 794 5678 Branch Offices Phone Number Fax Number Australia 03 9 879 9422 03 9 879 9179 Austria 0662 45 79 90 0 0662 45 79 90 19 Belgium 02 757 00 20 02 757 03 11 Canada Ontario 519 622 9310 519 622 9311 Canada Quebec 514 694 8521 514 694 4399 Denmark 45 76 26 00 4...

Страница 82: ...ficiently If you are using any National Instruments hardware or software products related to this problem include the configuration forms from their user manuals Include additional pages if necessary Name Company Address Fax Phone Computer brand Model Processor Operating system Speed MHz RAM MB Display adapter Mouse yes no Other adapters installed Hard disk capacity MB Brand Instruments used Natio...

Страница 83: ...ovember 1995 Part Number 371173A 01 Please comment on the completeness clarity and organization of the manual If you find errors in the manual please record the page numbers and describe the errors Thank you for your help Name Title Company Address Phone Mail to Technical Publications Fax to Technical Publications National Instruments Corporation National Instruments Corporation 6504 Bridge Point ...

Страница 84: ...round C Celsius CJC cold junction compensation dB decibels DC direct current DGND digital ground DIFF differential input mode F farads fc cutoff frequency GND ground Hz hertz in inches I O input output K kilobytes LED light emitting diode LSB least significant bit m meters MB megabytes of memory NBS National Bureau of Standards NRSE nonreferenced single ended input mode PS 2 Personal System 2 RSE ...

Страница 85: ...ing 5 3 board to board cabling SC 2070 board 2 5 to 2 6 SC 2071 board 3 5 to 3 7 SC 2072 board 4 6 breadboarding area specifications A 1 broken thermocouple detection SC 2070 board 2 18 to 2 19 thermocouple circuit with open themocouple detect figure 2 19 SC 2071 board 3 15 to 3 16 thermocouple circuit with open themocouple detect figure 3 16 C cabling See board to board cabling channel configurat...

Страница 86: ...d 2 19 SC 2071 board 3 16 thermocouple voltage output extremes SC 2070 board table 2 20 SC 2071 board table 3 17 getting started with SC 207X Series boards 1 4 ground referenced signal sources channel configuration 2 7 connecting SC 2070 board 2 9 differential inputs 2 9 single ended inputs 2 9 SC 2071 board 3 8 H hardware installation See installation highpass filters building SC 2070 board 2 13 ...

Страница 87: ...18 SC 2070 board 2 20 SC 2071 board 3 17 to 3 18 lowpass filters connecting to SC 2070 board 2 18 thermocouple circuit with lowpass noise filter figure 2 19 connecting to SC 2071 board 3 15 thermocouple circuit with lowpass noise filter figure 3 16 lowpass filters building SC 2070 board 2 10 to 2 11 lowpass filter on differential channel 1 figure 2 12 normalized frequency response figure 2 10 SC 2...

Страница 88: ...ith SC 207X boards table 5 8 installing 5 2 SC 207X Series boards See also specific devices computers supported 1 1 connections for DAQ devices figure 5 7 DAQ devices supported table 1 2 features 1 1 getting started 1 4 optional equipment 1 4 software 1 4 specifications A 1 to A 2 unpacking 1 5 SC 2070 board analog input 2 2 to 2 3 component positions in each channel table 2 3 onboard equivalent c...

Страница 89: ...ced signal sources 3 8 highpass filters building 3 10 to 3 12 lowpass filters building 3 8 to 3 10 soldering and desoldering 3 7 board to board cabling 3 5 to 3 7 connecting to incompatible boards warning 3 7 connection using SC 2053 cable adapter board figure 3 6 daisy chaining Lab 1200 devices to BNC 2080 figure 3 6 DAQ devices used with SC 2071 table 3 5 direct connection to Lab 1200 devices fi...

Страница 90: ...erenced signal sources 2 9 differential inputs 2 9 SC 2071 board 3 8 single ended inputs 2 9 nonreferenced or floating signal sources 2 7 to 2 8 differential inputs 2 7 to 2 8 single ended inputs 2 8 signals digital and timing SC 2070 board 2 4 to 2 5 SC 2071 board 3 5 single ended inputs ground referenced signal sources 2 9 nonreferenced or floating signal sources 2 8 single ended thermocouple me...

Страница 91: ...ruments Corporation Index 7 SC 207X Series User Manual purpose and use 2 17 3 14 timing signals SC 2070 board 2 4 to 2 5 SC 2071 board 3 5 U unpacking SC 207X Series boards 1 5 V voltage dividers See attenuators building ...

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