HYDRA

Service Manual

If the instrument powers up and displays ’boot,’ it is likely that one of the memory test errors (Errors 1 through 3) was detected. To determine what the error status was, connect a terminal or computer to the RS-232 interface (19200 baud, 8 data bits, no parity). Assuming that the RS-232 interface is functional, send a carriage return or line feed character to the instrument, and it should send back a prompt that shows a number followed by a ’>’ character. The number is interpreted in the same way as the responses for the *TST?and POWERUP? commands; refer to *TST? in Section 4 of the Hydra Data Bucket Users Manual. For example, a ’4>’ prompt indicates that the test of the NVRAM (A1U20 and A1U24) failed and the instrument was not able to safely power-up and operate.

Now send a ’t’ character followed by a carriage return to the instrument to request a retest of the firmware stored in Flash Memory. If both the boot firmware and the instrument firmware checksums are correct, the response will be as follows:

Boot image OK

Hydra image OK

0>

If the boot firmware checksum is not correct, the message "Bad boot image -- use at own risk!" might be seen. The code that must be executed to generate this message is part of the boot firmware that is bad, so there is no guarantee that this message will be seen.

If the instrument firmware checksum is not correct, one of the following error messages may be seen:

Bad rom pointer

"Invalid pointer to checksum structure"

Bad checksum pointer

"Invalid pointer to instrument checksum"

Bad checksum

"Incorrect instrument checksum"

Invalid instrument firmware may be corrected by using a personal computer to load new instrument firmware into the Hydra Databucket. To do this see the section entitled "Updating the 2635A Instrument Firmware" in Section 4 of this manual.

If the NVRAM (A1U20 and A1U24) do not operate correctly, the problem must be corrected before new instrument firmware may be loaded or the instrument can power up completely. Use an oscilloscope to check the activity of the address, data, and control signals to the NVRAM devices (A1U14 and A1U16). It may be necessary to continually reset (power on) the instrument to check these lines, since the activity probably halts quickly when the instrument software goes awry. To check the NVRAM control signals, verify that A1U1-127 is going low, propogating through A1U26, and also appearing on pins A1U20-22 and A1U24-22 of the NVRAM devices. Verify that RDU* (A1U11-14 and A1U24-24) goes low when A1U1-127 is low. Verify that RDL* (A1U11-19 and A1U20-24) goes low when A1U1-127 is low. If all this is true, the problem is with the NVRAM itself or there is a fault in the address/data lines from the MC68302 Microprocessor. It may also be useful to check signal continuity by using a DMM with the instrument power off. Verify also that pin 30 on A1U24 and A1U20 is pulled up to approximately 5.0 volts dc by resistor A1R45.

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Fluke 2635A, 2625A service manual 5A-20
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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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