GE Power Management
ALPS Advanced Line Protection System
1-21
1 PRODUCT DESCRIPTION
1.7 SELF-TEST FEATURES
1
1.7 SELF-TEST FEATURES
1.7.1 START-UP SELF-TESTS
The most comprehensive testing of the ALPS is performed during a power-up. Since the ALPS is not performing any pro-
tection activities at that time, tests (such as RAM tests) that would be disruptive to run-time processing are performed.
Both processors participate in the start-up self-testing. The processors communicate their results to each other so that any
failures can be reported and so that each processor successfully completes its assigned self-tests before the ALPS begins
protection activity.
During power-up, both microprocessors perform start-up self-tests on its associated hardware (including Flash Memory,
EPROM, local RAM, shared RAM, interrupt controller, timer chip, serial I/O ports, nonvolatile memory, analog and digital I/
O circuitry, and Keypad/LCD Display hardware). In addition, the ALPS verifies that the PROM version numbers on both pro-
cessor boards are compatible, and that the Model Number stored in nonvolatile memory agrees with the unit’s configura-
tion. The components tested at start-up are listed in Table 9–1: COMPONENTS TESTED DURING START-UP TESTS on
page 9–2.
In most cases, if any critical self-test failure is detected, the ALPS discontinues start-up and does not reset. It attempts to
store the ALPS status to initialize the KEYPAD/LCD DISPLAY and remote communications hardware/software for commu-
nicating the status. The critical alarm output is energized.
If no failures are detected, the ALPS completes initialization of its hardware and software; this includes reading information
from the serial Nonvolatile RAM (NVRAM) in the magnetic module, stored during the manufacturing process, to determine
the current rating of the magnetic in the unit (1 A or 5 A). Next, the 960 processor enables the outputs. As the final step, the
ALPS checks the results of all the tests to determine whether to turn on the green status LED on the front panel.
The start-up procedure takes approximately one minute. As soon as the 960 CPU successfully completes its PROM test
and initializes the display hardware, the message "INITIALIZING" appears on the display. When all ALPS initialization is
completed satisfactorily, the ALPS message is displayed and the ALPS begins acquiring and processing data.
1.7.2 RUN-TIME SELF-TESTS
Both of the processors have idle time when the ALPS is not performing fault or post-fault processing. During this idle time,
each processor performs background self-tests that do not interfere with the foreground tasks’ use of serial and parallel
ports and that do not inhibit interrupts to any processor. If any background self-test fails, the test is repeated. For a compo-
nent to be declared as failed, the test must fail three consecutive times. In the case of most critical failures, the ALPS forces
a reset to attempt to get the failed component working again.
The ALPS is able to distinguish between a start-up (power-up) and a reset caused automatically by a ALPS malfunction.
The reset is a fault-tolerant feature of the ALPS; it is performed as an attempt to resume operation after an intermittent fail-
ure. The reset activities are identical to the start-up activities except that not all start-up self-tests are performed. If the reset
was caused by failure of a specific background self-test, then only the start-up self-tests associated with that same hard-
ware are performed.
A reset is not reported by the ALPS. If the reset is successful no failure status is recorded and the critical alarm output is not
energized; however, during the reset procedure, the red LED on the front panel is lit and a failure code may appear on the
display. Therefore, if the reset is not successful, the processor board is shut down, leaving the Keypad/LCD Display dis-
playing the error information. Refer to Chapter 9.2.7: SERVICE SYSTEM STATUS FAILURES on page 9–5. To prevent
continual resets in the case of a solid failure, both hardware and software permit only four resets in a one-hour period. On
the fifth reset, the ALPS does not initialize, but attempts to initialize the display, communications, and the critical-alarm out-
put, as in the case of a start-up with a critical self-test failure. The reset procedure takes approximately one second,
depending upon which start-up self-tests are to be run.
The components tested in the background are listed in Table 9–2: RUN-TIME BACKGROUND SELF-TESTS on page 9–2.
Testing of I/O hardware is done in the foreground, so that the processors know when a given component or port is in use
and not available for testing. The components tested in the foreground are listed in Table 9–3: RUN-TIME FOREGROUND
SELF-TESTS. Some foreground tests are performed every sample period, while others are performed less frequently.
As with background self-tests, any failed foreground test is repeated and must fail three consecutive times to be considered
a failure. Although not specifically a self-test, the trip circuit continuity monitoring is performed as a foreground test. Refer to
Section 1.5.13: TRIP CIRCUIT MONITOR on page 1–18 of this chapter.
The operator may initiate a visual-response test of the KEYPAD/LCD DISPLAY components. Refer to Chapter 4: ACCEP-
TANCE/PERIODIC TESTS for details.
