Theory of Operation

Model GFC7000TA Carbon Dioxide Analyzer

The A/D can be configured for several different input modes and ranges but in the GFC 7000TA is used in uni-polar mode with a +5 V full scale. The converter includes a 1% over and under-range. This allows signals from –0.05 V to +5.05 V to be fully converted.

For calibration purposes, two reference voltages are supplied to the A/D converter: Reference Ground and +4.096 VDC. During calibration, the device measures these two voltages, outputs their digital equivalent to the CPU. The CPU uses these values to compute the converter’s offset and slope and uses these factors for subsequent conversions.

See Section 6.13.4 for instructions on performing this calibration.

9.3.6.2. Sensor Inputs

The key analog sensor signals are coupled to the A/D through the master multiplexer from two connectors on the motherboard. 100K terminating resistors on each of the inputs prevent cross talk from appearing on the sensor signals.

CO2 Measure and Reference

These are the primary signals that are used in the computation of the CO2 concentration. They are the demodulated IR-sensor signals from the sync demodulator board.

Sample Pressure and Flow

These are analog signals from two sensors that measure the pressure and flow rate of the gas stream at the outlet of the sample chamber. This information is used in two ways. First, the sample pressure is used by the CPU to calculate CO2 Concentration. Second, the pressure and flow rate are monitored as a test function to assist the user in predicting and troubleshooting failures.

9.3.6.3. Thermistor Interface

This circuit provides excitation, termination and signal selection for several negative-coefficient, thermistor temperature sensors located inside the analyzer. They are:

Sample Temperature Sensor

The source of this signal is a thermistor located inside the sample chamber of the Optical Bench. It measures the temperature of the sample gas in the chamber. This data is used to during the calculation of the CO2 concentration value.

Bench Temperature Sensor

This thermistor, attached to the sample chamber housing, reports the current temperature of the chamber housing to the CPU as part of the bench heater control loop.

Wheel Temperature Sensor

This thermistor (attached to the heat-sync on the GFC wheel motor assembly) reports the current temperature of the wheel/motor assembly to the CPU as part of the Wheel Heater control loop.

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Teledyne gfc 7000ta operation manual Sensor Inputs, Thermistor Interface
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gfc 7000ta specifications

The Teledyne GFC 7000TA is a cutting-edge, high-performance gas flow calibrator designed for both laboratory and field applications. This instrument is renowned for its accuracy, versatility, and reliability, making it an ideal choice for various industries, including aerospace, environmental monitoring, and manufacturing.

One of the standout features of the GFC 7000TA is its advanced measurement technology. It utilizes state-of-the-art thermal mass flow meters, which allow for precise fluid measurement across a wide range of flow rates. This technology ensures highly accurate readings, which are essential for applications requiring stringent compliance with regulatory standards.

The GFC 7000TA is capable of accommodating various types of gases, making it particularly versatile. Users can calibrate flow for gases such as air, nitrogen, or carbon dioxide, providing flexibility in a multitude of applications. The device also supports dual-channel capabilities, allowing simultaneous measurement and calibration of two different gas types, enhancing productivity and efficiency in processes.

Another notable characteristic of the GFC 7000TA is its user-friendly interface. Equipped with a high-resolution touchscreen display, the device offers intuitive navigation and data visualization. Users can easily set parameters, view real-time measurements, and generate printed reports. This interface reduces the learning curve for new operators, allowing organizations to implement the GFC 7000TA with minimal training.

In addition to its advanced measuring capabilities, the GFC 7000TA features a robust design for durability in harsh environments. The instrument is compliant with various international standards, ensuring its reliability and performance in various conditions. Its portable form factor makes it convenient for fieldwork, while the rugged construction provides peace of mind for users working in demanding settings.

The GFC 7000TA also incorporates modern connectivity options. With built-in USB and Ethernet ports, users can easily integrate the device into their existing systems for data logging and remote monitoring. This connectivity feature enables real-time data access and enhances the potential for analysis and optimization of gas flow systems.

In summary, the Teledyne GFC 7000TA is a high-performance gas flow calibrator characterized by its advanced thermal mass flow measurement technology, versatility in accommodating various gases, user-friendly interface, and robust design. With its modern connectivity features, this instrument stands out as a vital tool for professionals seeking precision and reliability in gas flow applications.
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