Sel SEL-DTA2, Инструкция по эксплуатации

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2.10
SEL-DTA2 Instruction Manual
Date Code 20020329
Specifications
Self-Tests
Self-Tests
The SEL-DTA2 runs an assortment of self-tests to ensure reliable operation.
This section describes each test and the steps taken if a test fails. The
instrument generates a report after any change in self-test status. All self-tests
are run on power-up and after use of the setting procedure. During normal
operation, all self-tests except the display test run every few minutes.
Random-Access
Memory
The instrument periodically checks random-access memory (RAM). If a byte
cannot be written to and read from, the SEL-DTA2 declares a RAM failure. It
transmits a STATUS message with the socket designation of the affected
RAM IC to serial Port 1. There is no warning state for this test.
Read-Only Memory
The SEL-DTA2 checks read-only memory (ROM) by computing a checksum.
If the computed value does not agree with the stored value, the instrument
declares a ROM failure and transmits a STATUS message to serial Port 1.
There is no warning state for this test.
Settings
Two images of the system settings are stored in nonvolatile memory. The
SEL-DTA2 compares them after initial commissioning and periodically
thereafter. If the images ever disagree, the setting test fails and the instrument
transmits a STATUS message to serial Port 1. There is no warning state for
this test.
Display
The display module is tested when the instrument is powered up, and as
described in the STANDBY display mode description. If a display module
failure is detected, the SEL-DTA2 sends an automatic status message to serial
Port 1.