Fluke 943-27, 943-227-15 manual Theory of Operation Main Circuit Boards, Bit Position Description

Page 15

Theory of Operation

2

Main Circuit Boards

Table 2-2. Electrometer Control Bit Assignments

Bit Position

7

6

5

4

3

2

1

0

Description

X

X

X

X

X

0

0

0

Gain = 1

X

X

X

X

X

0

0

1

Gain = 2

X

X

X

X

X

0

1

0

Gain = 4

X

X

X

X

X

0

1

1

Gain = 8

X

X

X

X

X

1

0

0

Gain = 16

X

X

X

X

X

1

0

1

Gain = 32

X

X

X

X

X

1

1

0

Gain = 64

X

X

X

X

X

1

1

1

Gain = 128

X

X

X

X

0

X

X

X

Unshort capacitor

X

X

X

X

1

X

X

X

Short capacitor

X

X

X

0

X

X

X

X

Digitize electrometer

X

X

X

1

X

X

X

X

Digitize high voltage

X = Bit position does not matter (1 or 0)

The integrating electrometer is formed by the combination of current source Z6, dual MOSFET Q4, operational amplifier Z12, transistor Q3, and analog switch Z17, pin 15.

Counter Z15 and ladder network RN3 form the auto-zero portion of the integrating electrometer. Refer to section 4 for auto-zero adjustment instructions (note this is a factory only adjustment).

Dual MOSFET Q4 acts as a low leakage input buffer to the electrometer. C17 is an integrating capacitor, while Z17, pin 15 and Q3 are the shorting elements of the integrator.

There is a hysteresis built into the range changing function of the electrometer. The range change-up occurs at the decade points whereas the range change-down occurs at 80% of the decade points. This hysteresis results in the display of only two significant digits when in the upper 20% of a decade. Whether or not this occurs depends on which direction the radiation level is trending. An increasing trend will result in three significant digits while a decreasing trend will result in two significant digits.

The response times for a change in reading within the same decade are listed in Table 2-1. If a change of 100 to 1000 times the current reading occurs, the instrument will range change within a single 50- millisecond clock cycle.

Table 2-3. Response Time

DECADE

RANGE

RESPONSE TIME

1

0.1 to 1.0 mR/h

80 sec.

2

1.0 to 10 mR/h

32 sec.

3

10 to 100 mR/h

16 sec.

4

100 to 1000 mR/h

4 sec.

5

1.0 to 10 R/h

2 sec.

6

10 to 100 R/h

0.9 sec.

7

100 to 1000 R/h

0.2 sec.

8

1.0 k to 10 kR/h

0.2 sec.

2-3

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Contents Victoreen Fluke Biomedical Table of Contents Blank General Information General DescriptionApplication Preamplifier Variations Application Detector Readout SpecificationsFeature Specification Preamplifier Power Jumper Normal Setting Function Cal. Position Switch Normal Switch FunctionOFF Selects 300 baud 1/ON Selects 4800 baud normal setting Jumper Normal Setting Function Alternate SettingDetector Connections TB1943-227-15 Description Connects To 977-210-10M J4-1Part Number Description Used On Auxiliary EquipmentRecommended Spare Parts Receiving InspectionStorage Blank Functional Description Theory of OperationFunction Hex Address Bit Position Description Theory of Operation Main Circuit BoardsRS232 Transmit Test Point FunctionRS232C Communications Victoreen Communications Loop 943-227-15VLJumper Normal Function Alternate Setting Enables Victoreen LoopJumper Normal Function Cal Setting Position Electrical Interface InstallationOperation Preamplifier MountingSet-up Digital Preamplifier Normal Operation Fail AlarmPower Failure OperationFirmware Version Configuration FunctionsTo B Enables Victoreen Loop To C Enables RS232C Normal To B Normal Operation To C PGA Offset AdjustSoftware Calculations Set Point Error CodesBlank Electronic Calibration Maintenance, Calibration and TroubleshootingMaintenance Electronic AdjustmentsTroubleshooting / Adjustments TroubleshootingConnector DESIGNATIONS, 943-227-15 and 943-227-15VL Connector DesignationsSwitch and Jumper POSITIONS, 943-227-15 and 943-227-15VL Related Manuals Not Supplied with this document Applicable Drawings 943-227-15VLBlank Bill of Materials Bill of Materials- 943-227-15 and 943-227-15VLPart Number Description Blank Cable Termination Instructions Cable Termination InstructionsDetector Cable Termination Digital Preamplifier HV Connector Notes HV Digital Preamplifier Cable Termination Instructions D Digital Preamplifier Appendix Cable Termination Instructions Digital Preamplifier Modification Sheets, Engineering Instructions Modification Sheets, Engineering InstructionsBlank Blank Fluke Biomedical

943-227-15, 943-27 specifications

The Fluke 943-27 and Fluke 943-227-15 are advanced electrical testing tools designed to meet the demands of professionals in industrial and commercial settings. Recognized for their accuracy and reliability, these devices come loaded with essential features tailored to ensure optimal performance during electrical measurements.

The Fluke 943-27 is a compact yet powerful multimeter that excels in providing precise voltage and current readings. It is equipped with a large, backlit display that ensures visibility in low-light environments. The device supports a wide range of testing parameters, including AC and DC voltage, resistance, continuity, and capacitance measurements, making it invaluable for troubleshooting electrical circuits.

On the other hand, the Fluke 943-227-15 offers additional capabilities, including advanced data logging features. This multimeter allows users to record and analyze measurements over time, which is particularly useful for identifying intermittent issues in electrical systems. Its connectivity options enable seamless data transfer to a computer or mobile device, facilitating easy documentation and reporting.

Both models illustrate a robust construction built to endure tough working conditions. They meet stringent safety standards, which is critical for protecting users from electrical hazards. The ergonomic design ensures comfort during prolonged use, and features like overmolding enhance grip and durability.

One of the standout technologies in these multimeters is Fluke’s True-RMS measurement capability. This feature ensures accurate readings of non-linear loads, which are common in modern electrical systems with variable frequency drives and other electronic devices. Additionally, the built-in low-pass filter technology reduces noise in measurements, ensuring precision even in environments with significant electrical interference.

The Fluke 943-27 and 943-227-15 are also designed to be user-friendly. They feature intuitive controls and a straightforward user interface, allowing technicians to navigate functions effortlessly. The ability to perform automatic ranging simplifies measurements, eliminating the potential for errors when setting the range manually.

In conclusion, the Fluke 943-27 and 943-227-15 represent essential tools for electrical technicians who require versatility, accuracy, and durability in their testing equipment. With advanced features, reliable technologies, and a user-centric design, these multimeters not only meet but exceed the expectations of professionals in the field.
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