Power Meter Operation
Self Test
•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.
•RS232/RS422 Loop Back - A message is sent via the UART and transceivers using an external loop back connector (refer to the E4418B/E4419B Service Guide).
Option 001 Battery
This test checks that the capacity of the option 001 battery has not decayed below 70 % of its original value. The test is only performed on power meters fitted with option 001.
Calibrator
The reference calibrator is turned on (indicated by the POWER REF LED) and measured internally. A pass or fail result is returned.
Keyboard (Front Panel only)
The power meter enters a mode where you are invited to press any key. When a key is pressed, its name appears on the screen. You can check that the power meter is displaying the expected name when the relevant key is pressed. This is a check that the power meter is receiving the correct keyboard signal. Pressing the same key twice sequentially exits this mode and returns you to a display that lists all the keys that were not entered. If the test is exited without all the keys being pressed a list is displayed showing all the keys which were not selected.
Display
Three tests are available for the display: the display assembly, display RAM and bitmap display.
A read/write is performed on the display RAM. If the value which is written is read back correctly, a pass is recorded, otherwise a fail is recorded.
The liquid crystal display/ light emitting diode (LCD/LED) control circuits are tested by making separate voltage measurements via the multiplexer and digital signal processor. If the expected voltages are measured, a pass is recorded, otherwise a fail is recorded. The three circuits which are tested are the LCD contrast control, the LED brightness control and the display temperature sensing diode.
HP E4419B User’s Guide |
