Theory of Operation 4

Detailed Circuit Description

High Voltage Power Amplifier Assembly (A3)

Power amplifier

Harness to heat sink and its high voltage power devices

Connections to the output transformers

High voltage heat sink temperature monitoring circuitry

High Voltage Sense Assembly (A6):

High voltage sense (attenuator) and calibration circuits

5725A input and output switching relays, relay drivers

Analog monitor, an 8-bit dac, latch for mux, latch for dac

Subminiature D-type connector to the 5700A

5700A current routing circuits

Guard crossing

AC line power selection circuitry

AC line inrush current limiting circuitry

Detailed Circuit Description

4-14.

Detailed circuit descriptions for each pca (printed circuit assembly) are provided next. Individual block diagrams are provided for the Current Amplifier (A2), High Voltage Amplifier (A3), High Voltage Sense (A6), and Digital (A5) assemblies. You may also find it helpful to refer to the schematic diagrams (Section 9) while reading theory for each assembly.

Interconnect Assembly (A1)

4-15.

The Interconnect assembly (A1) links the other five assemblies in the 5725A. The interconnect assembly contains the following parts:

Connectors and traces to interconnect the other assemblies and the fan. There are three 32-pin DIN connectors on the Interconnect pca which connect the Power Supply assembly (A4), High Voltage Amplifier assembly (A3), and Current Amplifier assembly (A2). A 64-pin DIN connector links the Interconnect assembly to the High Voltage Sense assembly (A6). A 34-pin ribbon cable connector links the Interconnect assembly to the Digital assembly (A5). Other cable assemblies attached to the Interconnect assembly go to the fan, High Voltage assembly output, and high voltage transformers.

High voltage transformer secondary-switching circuitry. Three high voltage reed relays (K013, K014, and K015) select one of three ac voltage output transformers. A fourth relay (K001) is a high voltage armature type that connects the secondaries of the low-frequency transformer in either a series or parallel fashion.

The circuit board has four layers. Most connections are done on the inner two layers. One outer layer is an earth ground plane; the other outer layer is tied to the signal VCOM.

4-11

Page 69
Image 69
Fluke 5725A instruction manual Detailed Circuit Description, Interconnect Assembly A1

5725A specifications

The Fluke 5725A is a high-performance, multifunctional temperature calibration source designed to meet the demanding requirements of laboratory and industrial environments. Renowned for its accuracy, reliability, and versatility, the 5725A serves as a powerful tool for engineers and technicians engaged in temperature calibration processes.

At the core of the 5725A is its advanced measurement technology, which allows for precision temperature calibrations across a wide range. With an operating temperature range from -200°C to 660°C, it caters to various applications, making it suitable for calibrating thermocouples, resistance temperature detectors (RTDs), and other temperature measurement devices.

One of the standout features of the Fluke 5725A is its outstanding accuracy, boasting a specified uncertainty of just ±0.15°C. This level of precision ensures that users can maintain compliance with regulatory standards and regulatory requirements in fields such as aerospace, pharmaceuticals, and manufacturing.

The Fluke 5725A is equipped with dual-channel capabilities, allowing users to calibrate two devices simultaneously. This enhances productivity by minimizing downtime and optimizing workflow efficiency. The intuitive touchscreen interface simplifies operations, enabling users to view measurements, set up test parameters, and access historical data with ease.

Versatile connectivity options such as USB and Ethernet enable seamless integration into existing systems and allow for data transfer, remote control, and configuration. This feature empowers technicians to conduct calibrations efficiently, whether on-site or remotely.

The robust design of the Fluke 5725A ensures its durability in demanding environments. Built with high-quality materials, it is resistant to shocks and vibrations, making it suitable for use in manufacturing plants and laboratories where equipment may be subjected to harsh conditions.

Another notable characteristic of the 5725A is its ability to generate stable temperature outputs with minimal drift, contributing to consistency in calibration results. Its built-in self-test functionality helps ensure that the unit remains in peak operating condition, giving users confidence in their calibration processes.

In summary, the Fluke 5725A is a top-tier temperature calibration source that excels in accuracy, reliability, and user-friendliness. Whether in laboratory settings or industrial applications, its advanced technologies and features make it an essential tool for professionals tasked with maintaining precision in temperature measurements.