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Unformatted text preview: Number RC Filters and Attenuators for DAC0, DAC1, and TRIG1 Breadboard Area Temperature Sensor Product Name Pads for AI Conditioning 1 2 3 4 5 6 7 Pads R20 and R21 Switches S3, S4, and S5 68-Pin I/O Connector Fuse (0.8 A) Switches S1 and S2 Assembly Number and Revision Letter Screw Terminals Figure 2-1. SCB-68 Printed Circuit Diagram SCB-68 Shielded Connector Block User Manual 2-2 ni.com Chapter 2 Parts Locator and Wiring Guide To connect signals to the SCB-68, complete the following steps while referring to Figure 1-1, SCB-68 Parts Locator Diagram, and to Figure 2-1. 1. 2. 3. 4. Disconnect the 68-pin cable from the SCB-68, if it is connected. Remove the shielding screws on either side of the top cover with a Phillips-head number 1 screwdriver. You can now open the box. Configure the switches and other options relative to the types of signals you are using. Loosen the strain-relief screws with a Phillips-head number 2 screwdriver. Slide the signal wires through the front panel strain-relief opening. You can also remove the top strain-relief bar if you are connecting many signals. Add insulation or padding if necessary. Connect the wires to the screw terminals by stripping off 0.25 in. of the insulation, inserting the wires into the green terminals, and tightening the screws. Reinstall the strain-relief bar (if you removed it) and tighten the strain-relief screws. Close the top cover. Reinsert the shielding screws to ensure proper shielding. 5. 6. 7. 8. You can now connect the SCB-68 to the 68-pin I/O connector. Switch Configuration
The SCB-68 has five switches that must be properly configured to use the SCB-68 with the DAQ device. Table 2-1 illustrates the available switch configurations and the affected signals for each switch setting. Refer to Table 2-1 to determine the switch setting that applies to your application, and then refer to the following sections for more information on specific types of signals. National Instruments Corporation 2-3 SCB-68 Shielded Connector Block User Manual Chapter 2 Parts Locator and Wiring Guide Table 2-1. Switch Configurations and Affected Signals Switch Setting Applicable Signals Analog input, analog output, digital I/O, and timing I/O Temperature Sensor S5 S4 S3 Signal Conditioning Circuitry Power (Off) S1 S2 Direct feedthrough, with temperature sensor disabled and accessory power disabled Analog input and analog output1 Temperature Sensor S5 S4 S3 Signal Conditioning Circuitry Power (On) S1 S2 Temperature sensor disabled, and accessory power enabled2 Note: This configuration is the factory-default configuration. SCB-68 Shielded Connector Block User Manual 2-4 ni.com Chapter 2 Parts Locator and Wiring Guide Table 2-1. Switch Configurations and Affected Signals (Continued) Switch Setting Applicable Signals Single-ended analog input3 Temperature Sensor S5 S4 S3 Signal Conditioning Circuitry Power (On) S1 S2 Single-ended temperature sensor, with accessory power enabled2 Differential analog input
Temperature Sensor S5 S4 S3 Signal Conditioning Circuitry Power (On) S1 S2 Differential temperature sensor, with accessory power enabled2
1 When accessory power is enabled, I/O pin 8 is fused and is intended to be connected to +5V. This setting is not recommended for use with the NI 653X, NI 670X, or NI 660X. Refer to the device user manual at ni.com/manuals to determine if the device supplies +5 V to I/O pin 8. 2 Only applies to the signal conditioning circuitry. 3 Except NI 61XX devices. Refer to the device user manual at ni.com/manuals to determine if the device supports single-ended inputs. National Instruments Corporation 2-5 SCB-68 Shielded Connector Block User Manual Connecting Signals 3 This chapter describes the types of signal sources that you use when configuring the channels and making signal connections to the SCB-68, describes input modes, and discusses noise considerations to help you acquire accurate signals. Connecting Analog Input Signals
The following sections describe how to connect signal sources for single-ended or differential (DIFF) input mode. On most devices, you can software-configure the DAQ device channels for two types of single-ended connections--nonreferenced single-ended (NRSE) input mode and referenced single-ended (RSE) mode. RSE input mode is used for floating signal sources. In this case, the DAQ device provides the reference ground point for the external signal. NRSE input mode is used for ground-referenced signal sources. In this case, the external signal supplies its own reference ground point, and the DAQ device should not supply one.
Note Some devices might only support one of the possible input modes. Input Modes
You can configure the DAQ device for one of three input modes--NRSE, RSE, or DIFF. The following sections discuss the use of single-ended and differential measurements and considerations for measuring both floating and ground-referenced signal sources. On devices that support both single-ended and DIFF input modes, using DIFF input mode commits two channel...
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This note was uploaded on 05/19/2012 for the course ELEN 3030 taught by Professor Joshi during the Spring '12 term at Marquette.
- Spring '12