Performance Testing and Calibration

4

Calibration

Activate calibration mode by pressing and holding the CAL Enable button (front panel) for approximately 4 seconds. Release the button after Hydra beeps and the CAL annunciator lights.

Note

The CAL Enable button is located on the right side of the display and is recessed beneath a calibration seal. Press this button with a blunt-tipped object. Avoid using a sharper-tipped object (such as a pencil). Do not press CAL ENABLE unless you intend to calibrate the instrument. If you have activated Calibration and wish to exit calibration immediately, press CAL ENABLE momentarily a second time.

The instrument must be stabilized in an environment with ambient temperature of 22 to 24ºC and relative humidity of less than 70% and have been turned on for at least 1/2 hour prior to calibration.

The instrument should normally be calibrated on a regular cycle, typically every 90 days or 1 year. The chosen calibration cycle depends on the accuracy specification you wish to maintain. The instrument should also be calibrated if it fails the performance test or has undergone repair.

The instrument features closed-case calibration controlled over the Computer Interface. Using known reference sources, closed-case calibration has many advantages. There are no parts to disassemble, no mechanical adjustments to make, and the instrument can be calibrated by an automated instrumentation system.

Once the instrument is in calibration mode, closed-case calibration can be made for the four calibration groups: Volts DC, Volts AC, Resistance, and Frequency. Once begun, each group must be completed successfully for the results of the calibration to be made permanent. It is not necessary to perform all calibration groups. Each group is independent of the other three groups; completion of a group sets the constants for that group.

Analog inputs are made at the rear-panel Input Module, and computer interface commands are used to control each step of the process. Either of the following two closed-case calibration procedures can be used:

∙Using Hydra Starter Calibration Software

This procedure uses software supplied with this Service Manual.Instructions for each step are presented on the PC screen.

∙Using a Terminal

This procedure relies on individual commands for each step. A summaryof these commands is presented in Table 4-8.

With either closed-case procedure, an additional procedure (reference junction calibration) may be used to calibrate the thermocouple temperature function. This procedure requires physical access to the rear panel Input Module.

Note

The instrument returns a Device Dependent Error prompt (!>) if a calibration step fails. Usually, this happens if the reference is not within an anticipated range (5 to 15%, depending on the step). At this point, the response to the CAL_STEP? command equals the raw, uncalibrated reading taken on the reference input. Refer to Calibration Failures in Section 5 for more information.

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Fluke 2625A, 2635A service manual Performance Testing and Calibration
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2635A, 2625A specifications

The Fluke 2625A is a sophisticated data logger designed for a wide range of industrial and laboratory applications. This versatile instrument excels in capturing and monitoring temperature and voltage measurements with precision and reliability. One of its standout features is its ability to record data from various sensors, making it ideal for environments where comprehensive data acquisition is critical.

Equipped with a large LCD display, the Fluke 2625A provides clear and user-friendly access to real-time measurement data. Its graphical interface allows users to visualize trends and monitor readings easily, which significantly enhances usability. The device supports a variety of input types and can connect to thermocouples, RTDs, and other sensors, offering great flexibility for various measurement tasks.

The Fluke 2625A employs advanced measurement technologies that ensure accuracy in data logging. With a high sampling rate, it captures fast-changing signals while maintaining data integrity. The device features a built-in memory that allows for extensive logging, accommodating long-term monitoring tasks without requiring constant oversight. Users can set it to log data at specified intervals, offering customizable solutions for different monitoring needs.

Another significant characteristic of the Fluke 2625A is its robust communication capabilities. The device supports USB and RS-232 interfaces for easy connectivity with computers and other devices, making data transfer and analysis seamless. This feature is especially beneficial for users who need to compile or analyze large sets of data quickly.

Furthermore, the Fluke 2625A is designed with durability in mind. Its rugged construction makes it suitable for challenging environments, including those with high levels of vibration, dust, or moisture. This reliability ensures that the device can withstand the rigors of fieldwork while still delivering accurate measurements.

In summary, the Fluke 2625A is a powerful data logger that combines versatility, accuracy, and reliability. Its user-friendly interface, advanced measurement technologies, and robust design make it an essential tool for professionals in various industries, from manufacturing and HVAC to research and development. Whether monitoring temperature changes in a laboratory or assessing voltage levels in an industrial setting, the Fluke 2625A stands out as a trusted solution for effective data logging and analysis.
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