Digital Kernel; Display Assembly; Ieee-488 Interface Option (-05); Battery Pack Option (-01) - Fluke 45 Service Manual

2-9.

Digital Kernel

The Digital Kernel functional block is responsible for the coordination of all activities
within the meter. This block requires power supply voltages from the Power Supply and
reset signals from the Display Assembly.
Specifically, the Digital Kernel Microprocessor performs the following functions:
•
Executes the instructions in ROM
•
Stores temporary data in RAM
•
Store meter configuration and calibration data in EEROM
•
Communicates with the Analog Measurement Processor via the Serial
Communication (Guard Crossing) block
•
Communicates with the Display Controller to display readings and user interface
information
•
Scans the user interface keyboard found on the Display Assembly
•
Communicates via the RS-232 interface and optional IEEE-488 interface.

2-10. Display Assembly

The Display Assembly controller communicates with the main Microprocessor over a
three-wire communication channel. Commands from the Microprocessor inform the
Display Controller how to modify its internal display memory. The Display Controller
then drives the grid and anode signals to illuminate the required segments on the
Display. The A2 Display Assembly requires power supply voltages from the Power
Supply and a clock signal from the A1U6 Microprocessor.

2-11. IEEE-488 Interface Option (-05)

Theory of operation for the IEEE-488 Interface Option (-05) is presented in Chapter 8 of
this manual. The related schematic diagram is found in Chapter 9.

2-12. Battery Pack Option (-01)

Chapter 7 of this manual contains the theory of operation for the Battery Pack Option
(-01). Refer to Chapter 9 for the related schematic diagram.

2-13. Detailed Circuit Description

2-14. Power Supply Circuit Description

The Power Supply consists of the following three functional sections:
•
Raw DC Supply
The Raw DC Supply converts line voltage (90 V to 264 V ac) to a dc output of 7.5 V
to 5 V.
•
5 V Switching Supply
The 5 V Switching Supply converts the Raw DC Supply output to 5.1 V ± 0.25 V dc.
•
Inverter
Using the 5 V Switching Supply output, the Inverter generates the -30 V dc, -5 V dc,
and 5 V ac supply levels needed for the vacuum-fluorescent display. Also, the
Theory of Operation

Detailed Circuit Description

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