Test Descriptions - Agilent Technologies E4418B User Manual

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 Agilent E4418B/E4419B Service
Guide.
• UART Configuration - confirms that the baud rate, stop bits and parity
settings are correctly configured on the UART.
• Local Loop Back - Tx and Rx on the UART are internally connected and a
test message is sent to confirm correct operation.
Agilent E4418B User's Guide
Power Meter Operation
Self Test
2-69