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EX10xxA Introduction 17
The EX10xxA is as easy-to-use as it is powerful. An integrated web page provides a convenient
way to instantly verify communications and instrument functionality, while industry standard VXI
plug & play and IVI drivers provide a familiar application programming interface to reduce
integration and program development time.
FEATURES
Combined Thermocouple and Analog Inputs
Easily combine thermocouple and analog signals on these versatile instruments with sampling
rates up to 1 kSa/s (kilosamples per second) per channel. Each input incorporates an independent
signal conditioning path with software selectable filters for maximum flexibility. Complete
channel independence ensures data integrity regardless of sample speed or input overload
conditions.
End-to-end Self-calibration
Complete end-to-end self-calibration is provided for each signal path on a programmable basis. A
highly accurate calibration source provides reference signals that are applied prior to analog
filtering and gain circuits to compensate for drift, aging, or temperature variations. Self-calibration
is simple and quick, and can be performed as often as desired.
Scalable for Synchronized High-Speed, High-Channel Count
With LXI™ Class A compliant features like a built-in Trigger Bus™ hardware trigger subsystem,
the EX10xxA supports easy integration and synchronization of multiple devices, including
existing VXIbus instrumentation.
Note: LXI Class A compliance for RX1032 is in progress.
Open Thermocouple Detection (OTD)
While the integration of the EX10xxA removes many of the reliability and connectivity problems
typically faced by system designers, they still must contend with the reliability of the sensor
connections. Fortunately, the EX10xxA aids a great deal in that regard as well. Each thermocouple
input channel generates a very small current (±7.5 nA/channel) which drives the input to an open-
circuit state if the transducer is disconnected. Implemented in this way, open transducer detection
is continuous and requires no discrete function call on the part of the user to be activated, offering
more protection than systems that only check on command, as a broken sensor can occur at any
time during testing, not just at installation. In a typical application, the OTD has no effect on the
measurement. However, many thermocouple simulators have a much higher impedance than a
thermocouple so an offset may be introduced into the reading when using a simulator. In general,
the OTD should only be active on channels that are being used with actual thermocouples.
The EX10xxA additionally offers a front panel OTD LED for each channel that illuminates upon
the recognition of a fault condition. This provides for quick and easy problem channel
identification. Moreover, to ensure that even intermittent problems are identified, the fault
recognition is a latching mechanism, retaining the information of the current acquisition sequence
until a new acquisition is initiated. Note that voltage channels do not include internal CJC
thermistors, but that each voltage D-sub includes connections for the connection of user-supplied
thermistors.
Cold Junction Compensation (CJC)
For highest accuracy and stability, the EX1000A-TC, EX1016A, EX1032A, EX1048A and
RX1032 provide embedded isothermal input sections that are monitored by twelve precision
thermistors (based on Model#, the number of thermistors can vary), one for every four
thermocouple channels. (Note, the EX1000A may utilize external thermistors as described in the
Voltage Connections section). To ensure that the CJC information is current and time correlated