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Fluke 2625A, 2635A service manual Variations in the Display

Models: 2635A 2625A

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Diagnostic Testing and Troubleshooting (2620A/2625A)

5

Variations in the Display

5.Verify that the DISRX signal (A2U1-39) goes low after RESET (A2U1-1) goes low. If this sequence does not occur, communication to the Microprocessor is held off with the DISRX signal high. If DISRX stays high but is not shorted to VCC, A2U1 must be faulty.

6.Verify activity for both the DISTX and DSCLK signals. These signals are driven by the Microprocessor and must be transitioning for the Display Controller to receive commands from the Microprocessor.

7.If all segments of a particular digit do not turn on at power-up, the grid drive from A2U1 may not be connected properly to A2DS1. Grids are numbered from 10 to 0 (left to right as the display is viewed). For a digit to be enabled, the respective grid drive signals (GRID(10:0)) must be at approximately VCC (4.85 to 5.35V dc.) For a digit to be disabled, the drive must be at VLOAD (-28.5 to -32.0V dc.)

8.If a segment under each of several (or all) grids fails to be turned on (or off) properly, one of the anode drive signals may not be connected properly from A2U1 to A2DS1. When an anode signal is at VCC, and a grid signal is at VCC, the corresponding segment on the display is illuminated.

9.If the Microprocessor has difficulty recognizing front-panel button presses, the switch scanning signals (SWR1 through SWR6, A1U4-21 through -26, respectively)

should be checked. When no switch contacts are being closed, the switch scanning lines should have about 20 kΩ of resistance between each other (through two 10-kΩpullup resistors to VCC). Unless one of the switches is closed, none of the switch scanning lines should be shorted directly to GND at any time.

5-19. Variations in the Display

Note

The following procedure will not work with Hydra’s Mainframe Firmware version 5.5.

Under normal operation, the display presents various combinations of brightly and dimly lit annunciators and digits. However, you may encounter other, random irregularities across different areas of the display under the following circumstances:

∙After prolonged periods of displaying the same information.

∙If the display has not been used for a prolonged period.

This phenomenon can be cleared by activating the entire display and leaving it on overnight (or at least for several hours). Use the following procedure to keep the display fully lit:

1.With power OFF, press and hold SHIFT, then press power ON.

2.Wait a moment for the instrument to beep, then release SHIFT. The entire display will now stay on until you are ready to deactivate it.

3.At the end of the activation period, press any button on the front panel; the instrument resumes the mode in effect prior to the power interruption (Active or Inactive.)

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Fluke 2625A, 2635A service manual Variations in the Display
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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.