2620A/2625A

Users Manual

The floating point format used is 32-bit with a 1-bit sign, 8-bit exponent, and 24-bit mantissa with the most significant bit hidden under the LSB of the exponent. The number is formatted as shown in Table F-1.

Table E-1. Floating Point Format

sign 1 bit

 

exponent 8 bits

 

 

 

 

 

mantissa 23 bits (plus one hidden bit)

high byte (MMSB)

hi-mid byte (MLSB)

low mid byte (LMSB)

low byte (LLSB)

For all other measurement queries, Hydra Series II returns the string "+9E+9" for open thermocouple (OTC) measurement values. However, for the LOG_BIN?query, NaN (not a number) is returned instead. The IEEE floating point standard defines NaN as a positive, maximum exponent number with non-zero mantissa bits. Hydra Series II sets just the most significant mantissa bit, so the raw binary byte stream value is 7f c0 00 00 (hex).

For all other measurement queries, Hydra Series II usually returns ±1e9 for overload (OL) measurement values. However, for the LOG_BIN? query, Hydra Series II returns Inf (infinity) instead. The IEEE floating point standard defines Inf as a positive or negative maximum exponent number with a zero mantissa. Hydra Series II returns +Inf as the byte stream 7f 80 00 00 (hex) and -Inf as ff 80 00 00 (hex).

The C code in Figure F-2 converts raw data into a useful format for the Intel x86 (IBM PC) architecture. The BCD time stamp is converted to integers, and floating point numbers created for the totalizer and measurement values.

Example

Figure F-3 is a short example that uses the routines in Figures F-1 and F-2 to decode a fixed (pre-computed) LOG_BIN? response string.

When compiled and run on an Intel architecture computer, the program should print "Conversion worked".

Although this example is useful for educational purposes, it is not very efficient. If desired, the decoding and conversion processes can be combined into a single, fast algorithm.

E-4

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Fluke 2625A, 2620A user manual Example

2625A, 2620A 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.