Fluke NetDAQ 2640A, Service Manual

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NetDAQ
Service Manual
2-8
•
Communicates with the microprocessor on the A/D Converter PCA via the Serial
Communication (Guard Crossing) block (A1U5, A1U7).
•
Communicates with the Display Controller to display readings and user interface
information (A1U1, A1U31).
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Communicates with the Field Programmable Gate Array (A1U31), which scans the
user interface keyboard found on the Display Assembly and interfaces with the
Digital I/O hardware.
•
Communicates with a host computer via the Ethernet interface (A1U32).
•
Communicates with a host computer via the RS-232 interface (A1U1, A1U13).
•
Reads the digital inputs and changes digital, alarm, and trigger outputs.
Serial Communication (Guard Crossing) 2-6.
This functional block provides a high isolation voltage communication path between the
Digital Kernel of the Main PCA and the microprocessor on the A/D Converter PCA.
This bidirectional communication circuit (A1U5, A1U7) requires power supply voltages
from the Power Supply block.
Digital Inputs and Outputs 2-7.
This functional block contains the Totalizer and Trigger Input buffers, eight bidirectional
Digital I/O channels (A1U3, A1U4, A1U17, A1U27), Master Alarm output, and a
Trigger Output (A1U17). These circuits require power supply voltages from the Power
Supply and signals from the Digital Kernel.
Ethernet Interface 2-8.
This functional block contains the Ethernet Controller (A1U32), used for both 10BASE2
and 10BASE-T. When 10BASE2 is selected by the Ethernet interface, an additional
Ethernet Transceiver device (A1U32) is used. These circuits require power supply
voltages from the Power Supply and signals from the Digital Kernel.
A2 Display PCA Block Description 2-9.
The Display Assembly controller communicates with the A1 Main PCA microprocessor
(A1U1) over a three-wire communication channel. Commands from the microprocessor
inform the Display Controller how to modify its internal display memory. The Display
Controller (A2U1) then drives the grid and anode signals to illuminate the required
segments on the Display. The A2 Display PCA requires power supply voltages from the
A1 Main PCA power supply voltages and a clock signal from the A1U4 microprocessor.
A3 A/D Converter PCA Block Description 2-10.
The following paragraphs describe the major blocks of circuitry on the A/D Converter
PCA.