Selecting The Self-Test; Self-Test Limits - HP 3456A Operating And Service Manual

Service
8·321. Selecting the Self·Test.
8-328. When the test is enabled, by pressing the TEST
button, the instrument starts a routine in which 1 2 in­
dividual tesls are perrormed. The test routine is:
a. The LEDs are lit and the display shows
" + 1.8.8.8.8.8. + 8." .
b. All fronl panel display and LEDs are blank.
c. Test #1 through #12 are sequentially executed.
d. The loop is repeated until the TEST button is
pressed again.
NOTE
Make sure no connection is made at the
3456A 's Input Terminals and the GUARD
switch is in the "IN" position during the
Test mode.
8-329. If no railures are detected during the test, the
34S6A alternately lights and blanks the display. I f a test
fails, a negative integer which corresponds to the fa iled
test is displayed. When this happens, the 34S6A does
nOI do any or the other tests, it will remain in the failed
test mode until the test passes or the instrument is taken
out of the Test mode. The tests are normally done in
order rrom #1 to #12.
8-330. The failed test and any other test can be in­
dividually selected rrom the front panel, to simplify
troubleshooting. Select a test this way:
a. Press the TEST button (if not in the Test mode).
b. Enter the desired test number (1-12) rrom the
keyboard .
c.
Press the STORE button.
d. Press the "5" (COUNT register) key on the
Numbered Keyboard.
8-33 1 . Using this method the 34S6A remains in the
selected test mode until the 34S6A is taken out of the
Test mode (by pressing the TEST or RESET button).
8-332. When a test is selected, certain inrormation is
displayed. If Test # I , 2, or 3 is selected and the test
passes, a + I , + 2, or + 3 is displayed, respectively. I f
the test(s) fail, a - I , -2 , or
tively. For tests 4 through 12, the AID Converter's out­
put is displayed. Since the selected test is continually ex­
ercised and the converter output is displayed, the faulty
circuitry can be checked in the inoperative state.
S-333. Test number
2, and 3 are digital tests and
1 ,
numbers 4 through 1 2 are analog tests. The tests
parameters are listed in Table S-14 and are explained as
follows. Remember, the AID output is only displayed if
an individual test is selected.
8-58
- 3 i s displayed, respec­
Tlble 8·14. 3456A Self·Test Limits.
.�
fitt .. Do.,
- - - -
,
-
- - -
-
- - -
2
On ou
J
•
0
, .08
0 ou
OU
,
5 0 .08
,
0 ou
0 .08
6
,
00
' 0 .08
0
,
00 OU
ou
8 . .08
On
OU
.o,
.08
9
00 ou
.8
> 0 ' 0
ou ou
, .08
, .08
a. Test # 1 . This test checks the Program Memory
RAM. It is accomplished by writing "0" into the RAM
and then reading "0" rrom the RAM. The same is done
with writing and reading " I " . The sequence is repeated
for each byte in the RAM.
b. Test #2. This test verifies that the Outguard's
Microprocessor is runctional. It is done by doing the
34S6A's Math calculations and checking the results.
c. Test 113. This test verifies the Isolation Logic. It is
done by sending a hexadecimal "SF" from the outguard
to the Inguard Controller. The controller then sends
back to the Outguard either a hexadecimal "8F" or
"9F". depending on the FrontlRear switch position.
d . Test #4. In this test the Input Amplifier is set-up
ror the X I gain configuration with its input shorted to
ground (Autozero On). The output of the AID Conver·
tor (Input Amplifier orrset) is displayed on the rront
panel. checking the circuitry between and including the
Input Amplifier and AID Converter.
e. Test 115. This is the same as Test #4 with the Input
Amplifier set to the XIO gain configuration.
f. TeSI #6. This is the same test as Test 114 and 115
with the Input Amplifier set to the X l OO gain configura­
tion.
g. Test 117. The - 12 V reference voltage is applied to
the Input Amplifier with the resultant output of the
AID Converter displayed. The Input Amplifier is in the
XI gain configuration.
h. Test I# S . The AC Converter's offset is checked
with its input relay open.
i. Test 1#9. The AC Converter's offset is checked
with its input relay closed.
j. Test 1110. The 500 nA current source is applied to
the top of the 10 M ohm resistor of the 100:1 Divider.
The output voltage of the divider (voltage across the 100
K ohm resistor) is connected to the Input Amplifier with
the amplifier in the X2 gain configuration.
Model 34S6A
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