HP4402.book : chapter2.fm 70 Thu Feb 11 15:53:59 1999
Power Meter Operation
Self Test
2-70 HP E4418B User’s Guide
Test Descriptions
This section specifies what is actually checked by each of the tests. Some
of the tests may only be applicable to one method of invocation (for
example, from the front panel). If this is the case, it is specified in the test
description. Most of the tests have an associated error message which is
added to the error queue if the test fails. The exception to this is the
bitmap display test. Refer to Chapter 4, “Error Messages” for details on
these error messages.
ROM Checksum
This test calculates the checksum of the firmware and checks it against
the pre-defined checksum stored on the ROM. A pass or a fail result is
returned.
RAM
This test carries out a read and write test on the instrument RAM.
RAM Battery
When the firmware is first downloaded, a known value is written into a
battery-backed memory location. This test verifies that the value is still
resident. It returns a pass if the value is still present, otherwise it returns
a fail.
Measurement Assembly
A measurement assembly is requested to automatically run a self test.
This self test returns either a pass or a fail. A fail can either be produced
by the measurement assembly self test failing or by the measurement
assembly not responding.
Fan
This test confirms that the internal cooling fan is operating.
Serial Interface
Four tests are available for the serial interface: UART configuration, local
loop back, RS232 loop back and RS422 loop back. Both the RS232 and
RS422 loop back tests require a specially wired connector - refer to the
E4418B/E4419B Service Guide.
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