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USER GUIDE
SCC-TC Series Thermocouple
Input Modules
The SCC-TC Series thermocouple input modules, SCC-TC01 and
SCC-TC02, accept input signals from B-, E-, J-, K-, N-, R-, S-, and T-type
thermocouples. The thermocouple inputs are filtered and passed into a
differential amplifier with a gain of 100. The output of the amplifier passes
through a dual-pole 2 Hz filter. Each module contains thermistor circuitry,
powered by a 2.5 V reference, to compensate for cold-junction effects.
Each module
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When symbol is marked on a product, it denotes a warning advising you to take precautions to avoid electrical shock. When symbol is marked on a product, it denotes a component that may be hot. Touching this component may result in bodily injury. bold Bold text denotes items that you must select in the software, such as menu items and dialog box options. Bold text also denotes parameter names. italic Italic text denotes variables, emphasis, a cross reference, or an introduction to a key conce
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❑ Numbers 1 and 2 Phillips screwdrivers ❑ Wire insulation strippers ❑ NI-DAQ (current version) for Windows 2000/NT/XP Note Software scaling of measurements is not supported on the Macintosh operating system. Refer to the Converting Voltage Measurements to Temperature Measurements section for more information about measurement scaling. Unpacking the Module SCC modules are shipped in antistatic envelopes to prevent electrostatic damage (ESD) to the modules. ESD can damage several components on
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A blue stripe on the label identifies the SCC-TC0X as an analog input module. The label also displays the icon shown in Figure 1. TC Figure 1. SCC-TC0X Icon You can plug the SCC-TC0X into any analog input socket on the SC-2345. The socket you select determines which E Series DAQ device channels receive the SCC-TC0X signals. For single-stage input conditioning, plug the SCC-TC0X into any socket J (X +1), where X is 0 to 7, and connect the input signals to the module as described in the Conn
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3 2 1 The SCC-TC02 has a fixed screw-terminal receptacle and a removable screw-terminal block, as shown in Figure 2. 1 2 1 SCC Screw-Terminal Receptacle 2 Removable Screw-Terminal Block Figure 2. SCC-TC02 Two-Part Screw-Terminal System After you install the SCC-TC02, attach the input signals to the screw terminals of the module. 1. Remove power from the signal lines. 2. Strip 7 mm (0.28 in.) of insulation from the ends of the signal wires. 3. Insert the wires into the screw terminals. 4. Tigh
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The amplified thermocouple signal and cold-junction sensor signal are measured by E Series DAQ device channel X and channel X+8 respectively, where X is 0 to 7 depending on where you plug the SCC-TC0X. Refer to Figure 3 for SCC-TC0X signal connections. E Series SCC-TC0X DAQ Device Ref 5 V 10 MΩ Thermocouple Source 10 kΩ + 2-Pole Filter/ TC+ ACH(X ) 10 kΩ – Buffer Stage TC- Offset 10 MΩ Calibrator GND (SCC-TC02 only) Ref 5 V AISENSE 4.75 kΩ AIGND 1% 5 kΩ LM 4040 0.1% 2.5 V + 0.1 µF ACH(
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You can use the following formulas to convert the cold-junction sensor voltage to cold-junction temperature: T() °C = T – 273.15 K where T is the temperature in kelvin. K 1 T = -- ---- ---- --- ---- ---- ---- ---- --- ---- ---- ---- ---- --- ---- ---- -- - K 3 [] ab++ () lnR cR() ln T T where 3 a = 1.295361 × 10 4 b = 2.343159 × 10 7 c = 1.018703 × 10 R is the resistance of the thermistor in ohms. T V TEMPOUT --- ---- --- ---- ---- ---- ---- --- ---- ---- - R = 50 , 00 T 2.5 –V TEMPOUT
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Detecting Open Thermocouples The SCC-TC0X contains a 10 MΩ pull-up resistor that connects to +5 V to detect open thermocouples. To determine if you have an open thermocouple, check whether the corresponding E Series DAQ device channel is saturated. The pull-up and bias resistors saturate the channel by applying +2.5 V at the input of an open channel. This results in saturation to either the positive or negative rails of the E Series DAQ device (±10 V). Errors Due to Open-Thermocouple Detect
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NI-DAQmx Complete the following steps to configure the SCC-TC module using NI-DAQmx. 1. Open Measurement & Automation Explorer. 2. Right-click Devices and Interfaces and select Create New. 3. Under NI-DAQmx SCC Connector Block, select SC-2345. Click Finish. 4. In the SCC Connector Block Configuration window, configure the SCC system as follows: a. Specify the SCC Carrier Type. The location of the SCC sockets change depending on the SCC carrier type. b. Select the DAQ Device that is connected
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6. Under Accessory:, select SC-2345. 7. Click the Configure button. A new window appears listing the sockets (connector reference designators) of the SC-2345. 8. Select the SC-2345 socket where you installed an SCC. 9. Click Add and select the SCC you installed. If the module name does not appear in the list, either the module is not allowed in that location or you do not have the current version of NI-DAQ. If you do not have the current version of NI-DAQ, download it from ni.com. 10. If you
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8. Enter the specific values for your application in the Settings tab. Context help information for each setting is provided on the right side of the screen. 9. Choose the type of thermocouple you have connected to your SCC module. For the CJC Source parameter, select Built-In. 10. Click Test to test the channel. You should be able to view your measurement in the window that appears. You have finished configuring the NI-DAQmx task or global channel. Creating a Virtual Channel in Traditiona
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Calibrating the SCC-TC0X Using a Thermocouple Calibrator To calibrate the system using a thermocouple calibrator, complete the following steps: 1. Make sure that the thermocouple connections at both the SCC and the thermocouple calibrator are at the same temperature. 2. Connect the thermocouple calibrator to the SCC-TC0X. For best results, use thermocouple wire of the same length and type that you use in the thermocouple. 3. Set the thermocouple calibrator to the required calibration tempe
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where V is thermocouple voltage. TC V is E Series DAQ device voltage. ESERIES This step provides proper scaling for the thermocouple amplifier in the SCC-TC0X. 2. Measure the reference-junction (cold-junction) temperature. a. Read the thermistor voltage [ACH(X+8)]. b. Convert the thermistor voltage to cold-junction temperature using the formula in the Cold-Junction Sensor Output and Accuracy section. 3. Calculate the cold-junction compensation voltage by converting the cold-junction temperat
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Amplifier Characteristics 1 Open thermocouple detection current.....250 nA max (assuming floating thermocouple) 1 Common-mode rejection ratio................110 dB min 1 Output range ...........................................±10 V max Transfer Characteristics Gain ........................................................100 1 Gain error................................................±0.08% max 2 Gain stability...........................................±0.0005%/°C max 1 Offset error .............
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Thermocouple Temperature Maximum Typical Type Range (°C) Inaccuracy (±°C) Inaccuracy (±°C) K –200 to –100 2.5 1.25 –100 to 600 1.25 0.67 600 to 1,200 2 0.45 N –200 to –100 2.5 2 –100 to 1,300 2 0.7 R –50 to 0 3 1.24 0 to 100 2 0.82 100 to1,600 1.75 0.4 S –50 to 0 3 1.3 0 to 1,400 2 1 1,400 to 1,600 2.5 1 T –200 to –100 2.5 2 –100 to 400 1 0.9 Cold-Junction Sensor Cold-junction sensor accuracy ............... ±0.4 °C max from 15 to 35 °C, ±0.75 °C max from 0 to 15 °C and 35 to 55 °C Output.....
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Physical TC01 dimensions....................................7.8 cm by 2.92 cm by 1.85 cm (3.1 in. by 1.15 in. by 0.73 in.) TC02 dimensions....................................8.89 cm by 2.92 cm by 1.85 cm (3.50 in. by 1.15 in. by 0.73 in.) I/O...........................................................One 20-pin right angle male connector, 3-pin screw terminal system (SCC-TC02); two-prong mini-connector (SCC-TC01) Screw terminal field-wiring gauge (SCC-TC02) .................................28
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Note For UL and other safety certifications, refer to the product label, or visit ni.com/hardref.nsf, search by model number or product line, and click the appropriate link in the Certification column. Electromagnetic Compatibility Electrical emissions................................ EN 55011 Class A at 10 m FCC Part 15A above 1 GHz Electrical immunity................................ Evaluated to EN 61326:1997/ A2:2001, Table 1 CE, C-Tick, and FCC Part 15 (Class A) Compliant Note For full EMC
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I/O Connector Pin Assignments Figure 4 shows the I/O connector pins on the bottom of the module. 19 3 17 15 13 11 9 7 5 3 1 2 20 18 16 14 12 10 8 6 4 Figure 4. SCC Module Bottom View Table 1 lists the signal connection corresponding to each pin. ACH(X) and ACH(X+8) are the analog input signal channels of the E Series DAQ device. AIGND is the analog input ground signal and is the reference for ACH(X) and ACH(X+8). AGND is the reference for the ±15 V supplies and REF5V. AIGND and AGND connect
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Table 1. SCC Module Pin Signal Connections for SCC-TC0X Modules (Continued) Pin Number Signal 13 +15 V 14 –15 V 15 — 16 — 17 — 18 — 19 — 20 — © National Instruments Corporation 19 SCC-TC Series Thermocouple Input Modules User Guide
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National Instruments™, NI™, ni.com™, and NI-DAQ™ are trademarks of National Instruments Corporation. Product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National Instruments products, refer to the appropriate *323099B-01* location: Help»Patents in your software, the patents.txt file on your CD, or ni.com/patents. 323099B-01 Sep03 © 2002–2003 National Instruments Corp. All rights reserved.
