Agilent Technologies manual Agilent U2802A 31-Channel Thermocouple Input User’s Guide

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Features and Functions

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Figure 2-6Ground-referenced and differential signal sources configuration in U2802A

Zero mode: In zero mode, the positive and negative inputs of the instrumentation amplifier are shorted together. The output of the instrumentation amplifier is driven out to the corresponding AI channel. The voltage measured in this mode corresponds to the offset voltage of the channel. This voltage can be subtracted out of the subsequent thermocouple mode measurements in order to increase the measurement accuracy. Do take note that this mode only works for channels that have been configured to be in the thermocouple mode. Channels configured for bypass mode will not be affected when this mode is selected.

Each channel is equipped with an open thermocouple detection feature, where the 10 MΩ resistor is tied to the +15 V power supply rail. This feature can only be globally enabled or disabled for all channels, regardless of the channel mode setting. When enabled, outputs of the channels are set to thermocouple mode where the inputs are left open- circuited. This causes the positive power supply rail voltage (above +10 V) to be saturated up, indicating that the channel either has a broken thermocouple or the thermocouple is not connected. For channels set to bypass mode, channels with an open- circuited input will also be saturated to the positive supply rail voltage.

Agilent U2802A 31-Channel Thermocouple Input User’s Guide

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Contents Agilent U2802A 31-Channel Thermocouple Input Device U T I O N WA RN I N G Safety Information U2802A 31-Channel Thermocouple Input User’s Guide Regulatory Markings General Safety Information Do not dispose in domestic household waste Environmental Conditions This Guide November-2007 Regulatory Information for Australia/New Zealand XII Contents Calibration List of Figures List of Tables Getting Started Introduction to Agilent U2802A 31-Channel Thermocouple Input Product Outlook Product OverviewTop View Front ViewBottom View Side ViewTop View Front View Product DimensionsStandard Purchase Items Checklist Installations and Configurations Ii. If Agilent IO Libraries Suite 14.2 has Hard disk space 1 GB Check Your System RequirementsYou do not have the Agilent IO Libraries installed, or Check Your Pre-Installed IO Libraries SuiteIii. If Agilent IO Libraries Suite is not installed Getting Started Install the Agilent Measurement Manager Install the DAQ Hardware DriverGetting Started Agilent U2802A 31-Channel Thermocouple Input User’s Guide Getting Started Hardware Verification Connect Your DAQ Device to the PCConnect Your U2802A to DAQ Launch Your Agilent Measurement Manager Choosing Instrument-Specific Interface IVI-COM DriversChoosing Class-Compliant Interface IVI- COM Using Class-Compliant InterfaceProgramming Environments IVI-COM Driver InstallationGetting Started Agilent U2802A 31-Channel Thermocouple Input User’s Guide Getting Started Features and Functions Features Applications 1System overview of U2802A with DAQ System OverviewFunctionality of the System Theory of Operation3Functional block diagram for U2802A Functional Block DiagramAnalog input channel circuitry 4Functional block diagram for thermocouple mode in U2802A5Floating signal source configuration in U2802A Agilent U2802A 31-Channel Thermocouple Input User’s Guide Digital control Cold junction sensorTrigger, Counter, External Timebase, and Analog Output Open Thermocouple DetectionFeatures and Functions Pin Configurations and Assignments Pin Assignments Pin ConfigurationsPin Description Connector J71Pin Configurations and Assignments Connector J50 Pin Configurations and Assignments Pin Pin name Description Connector J60Rear panel pinout for Connector Connector Pinout3Connector 2 pin assignment for U2355A and U2356A Pin Configurations and Assignments Product Specifications Operating Environment General SpecificationsGeneral Characteristics Product CharacteristicsOther Features Accuracy on page 54 for calculation methodology System Accuracy SpecificationsWith different number of averaging points U2356A @ 0 C to 18 C and 28 C to 45 C Example Calculating System Accuracy= 0.02% × 33.102 mV = 6.62 µV = 6.62 µV ÷ 59 µV/C = 0.112 C System accuracy with thermocouple sensor error System accuracy without thermocouple sensor errorSystem Typical Performance Thermoelectric CharacteristicsTypical Error vs. Measurement Performance Making Accurate Temperature Measurements Product Specifications Calibration Calibration Information CalibrationZeroing Function Restore Factory Calibration Calibration Contact us