Allen-Bradley Compact 1769-IR6, Руководство пользователя

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Publication 1769-UM005A-EN-P
Overview 1-7
General Diagnostic Features
A single diagnostic LED helps you identify the source of problems that
may occur during power-up or during normal channel operation. The
LED indicates both status and power. See Chapter 5,
Diagnostics and
Troubleshooting , for details on power-up and channel diagnostics.
System Overview
The modules communicate to the local controller or communication
adapter through the 1769 bus interface. The modules also receive 5 and
24V dc power through the bus interface.
System Operation
At power-up, the module performs a check of its internal circuits,
memory, and basic functions. During this time, the module status LED
remains off. If no faults are found during power-up diagnostics, the
module status LED is turned on.
After power-up checks are complete, the module waits for valid channel
configuration data. If an invalid configuration is detected, the module
generates a configuration error. Once a channel is properly configured
and enabled, the module continuously converts the RTD or resistance
input to a value within the range selected for that channel.
Each time the module reads an input channel, it tests the data for a fault
(over- or under-range, short-circuit, or open-circuit condition). If it detects
a fault, the module sets a unique bit in the channel status word. See Input
Data File on page 4-2.
Using the module image table, the controller reads the two’s compliment
binary converted input data from the module. This typically occurs at the
end of the program scan or when commanded by the control program. If
the controller and the module determine that the data transfer has been
made without error, the data is used in the control program.
AB PLCs