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2.8 Self Test Operation
2.8.1 General
The PMC has two levels of built-in self-tests: a Function Test which checks for general functional
characteristics and a set of Diagnostic Tests which provide for detailed fault isolation. The
Function Test is performed automatically on power on and may be re-run at anytime by pressing
and holding both of the modify keys (Up/Down arrows) and depressing the RESET key. Pressing
the MODIFY DOWN key and depressing the RESET key will initiate the Diagnostic Tests.
Terminate the Function Test or Diagnostic Tests by pressing RESET.
2.8.2 Function Test Description
NOTE All PMC outputs must be isolated for proper Function Test Operation.
The Function Test is automatically performed during the power on sequence. The function test
verifies that the major subsections of the PMC are operating. Should a fault be detected, it can be
localized using the diagnostic tests (see the diagnostic test description for details, Sec. 2.8.3). It is
assumed that the Z80 control processor and its associated circuitry are operable in order to
perform the function test. An inoperable control processor would be immediately evident during
the power on sequence by random illumination of front panel LED's and a blank or incoherent
display. The PMC should be immediately switched off if this situation occurs; corrective
maintenance will be required.
The following information describes the various function tests that are performed. They are listed
in the order they are performed and each test references the PMC circuit subsection being tested.
If a failure occurs, a FAIL message will be displayed and no further tests will be performed.
Corrective maintenance must be performed before the PMC is placed in service.
2.8.2.1 DISPLAY AND LED TEST
All LED's and all elements of the alphanumeric display are illuminated during this test. The
flashing STORE LED, OVERLOAD AND HIGH VOLTAGE warning indicators are also
exercised. Defective LED's or display elements are easily noted for later corrective maintenance.
2.8.2.2 CONTROL FUNCTION TEST
During this test, the following key elements of the control section are tested.
1. Read Only Memory (ROM), which holds the PMC control program
2. Random Access Memory (RAM), which stores the measurement and operational data
3. Frequency generation and phase measurement counter circuitry
4. Electrically Erasable ROM (EEROM), which stores calibration and user data
5. Analog to Digital conversion circuitry (A/D).
The EEROM is not directly tested by the function test but is tested for loss or alteration of data
during power on and is tested each time the reset function or calibration operations are performed.
As mentioned above, it is assumed that a catastrophic fault is not present in the Z80 control
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