Theory of Operation (2635A) 2A

Introduction

2A-1. Introduction

The theory of operation begins with a general overview of the instrument and progresses to a detailed description of the circuits of each pca.

The instrument is first described in general terms with a Functional Block Description. Then, each block is detailed further (often to the component level) with Detailed Circuit Descriptions. Refer to Section 8 of this manual for full schematic diagrams. The Interconnect Diagram in this section (Figure 2A-1) illustrates physical connections among pca’s.

Signal names followed by a ’*’ are active (asserted) low. All other signals are active high.

2A-2. Functional Block Description

Refer to Figure 2A-2, Overall Functional Block Diagram, during the following functional block descriptions.

2A-3. Main PCA Circuitry

The following paragraphs describe the major circuit blocks on the Main PCA.

2A-4. Power Supply

The Power Supply functional block provides voltages required by the vacuum- fluorescent display (-30V dc, -5.0V dc, and filament voltage of 5.4V ac), the inguard circuitry (-5.4V dc VSS, +5.3V dc VDD, and +5.6V dc VDDR), and outguard digital circuitry of +5.0V dc (VCC).

Within the Power Supply, the Raw DC Supply converts ac line voltage to dc levels. The 5V Switching Supply converts this raw dc to 5.0V ±0.25V dc, which is used by the Inverter in generating the above-mentioned outputs. The Power Fail Detector monitors the Raw DC Supply and provides a power supply status signal to the Microprocessor in the Digital Kernel.

2A-5. Digital Kernel

The Digital Kernel functional block is responsible for the coordination of all activities within the instrument. This block requires voltages from the Power Supply and signals from the Power-on Reset circuit.

Specifically, the Digital Kernel Microprocessor performs the following functions:

∙Executes the instructions stored in FLASH EPROM.

∙Stores temporary data and nonvolatile instrument configuration datain NVRAM.

∙Stores instrument calibration data in FLASH EPROM.

∙Communicates with the microcontroller on the A/D Converter PCA viathe Serial Communication (Guard Crossing) block.

∙Communicates with the Display Controller to display readings and userinterface information.

∙Communicates with the Field Programmable Gate Array, which scans theuser interface keyboard found on the Display Assembly and interfaceswith the Digital I/O hardware.

∙Communicates with a host computer via the RS-232 interface.

∙Stores instrument setup and measurement data on a Static RAM memorycard installed in the Memory Card Interface Assembly.

∙Reads the digital inputs and changes digital and alarm outputs.

2A-3

Page 84 Page 86
Page 85
Image 85
Fluke 2625A, 2635A 2A-1. Introduction, 2A-2. Functional Block Description, 2A-3. Main PCA Circuitry, 2A-4. Power Supply
Page 84 Page 86

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.
Top Page Image Contents