HP 3457A - 8-80. Updated Self Tests 0, 1, and 2 (TEST)

then checked for accuracy. If the Main Controller finds an error in the returned data, the error
annunciator will flash and executing the AUXERR? command will return a value of 4,
During this procedure, the Main Controller will wait for a response from the A/D Controller. If the
Main Controller never receives a response from the A/D Controller then it will fall into diagnostic 2
and the display will indicate "FAILED".
The data is transmitted in 11 bit frames consisting of one start bit, 8 data bits, one parity bit and one
stop bit. The data is decremented from decimal 16 to decimal 1, with each of the patterns being in-
dependently checked for errors. The A/D Controller remains in the "ECHO BACK" mode until it
receives a decimal 0 data byte. At that time it will execute its ‘soft reset’ routine. This will set the A/D
Controller to its operational state where it will wait for the Main Controller to direct further activity.
A subset of self test 2 is diagnostic 2 which continuously sends only 4 distinct bytes, FF, OF, 55 and 01
between the A/D Controller and the Main Controller for troubleshooting purposes.
Test 3 is the integrator convergence test on assembly A2/2. This checks the ability of the A/D in-
tegrator (A2US512 and associated circuitry) to run-up from its reference current and then perform the
normal run-down and achieve the predicted result. The Main Controller (ATUSOL) configures the iso-
lated analog hardware (A2U501, A2U101, ete) for 3 volts DC and .0005 power line cycles integration
time, sends the last cal constants generated and opens the input terminal within the A/D hybrid
(A2US5I1) at pin 25.
The A/D Controller (A2U501) initiates a 10uS run-up using a known current, generated by A/D Hybrid
USI1, for a known period of time so the result is predictable. Run-down is executed, results are calcu-
lated and corrected using the last cal constants and the value is passed to the Main Controller for error
checking against the expected results. Figure 8-5 illustrates some of the circuitry used in this test.
On error, if the AUXERR? command is executed, the number 8 will be displayed on the control panel
if their are no other errors. This indicates an “Integrator Convergence Error’ (See Table 8-2).
A subset of test 3 is diagnostic 3 which causes the controller to continually loop through Test 3.
Executing DIAGNOSTIC 3 allows monitoring of signals while troubleshooting.
HP 3457A Multimeter
8-39