Maintenance 
CALIBRATION 
8. 
Select the  "lOOQ"  output  from  the  5450A and  cali- 
brate the 
high 
point for the 200Q range, entering the 
value computed  in  step 5 
as 
a  variable input. 
9. 
Select the 
"1 
kQ"  output  from  the  5450A and cali- 
brate the high  point  for the 
2 
kQ range, entering the 
value  computed  in  step 6 
as 
a  variable input. 
10. Calibrate the  remaining ranges  (steps 
D-G 
of  Table 
6-10) using  the  5450A outputs. 
11. 
Recalibrate the low point for each 2-wire ohms range 
using  a  shorting 
link 
(Pomona 
MDP-S-0 
or  equiva- 
lent) across the UUT's 
HI 
and 
LO 
INPUT 
terminals. 
12. 
Exit  the  calibration  mode  by  pressinn  the 
CAL 
13. 
Using  the  same  configuration shown in  Figure 6-4, 
verify that the UUT measures the same value (within 
1 
digit) in  2-wire ohms  (using the offset  feature to 
correct for  5450A floor error) 
as 
in 4-wire  ohms.  If 
the readings differ by  more than 
1 
digit, reenable the 
calibration mode  and repeat  steps  2  through 
8. 
14.  Cover  the  CAL 
ENABLE 
switch  with a  calibration 
certification sticker. 
6-23. 
Remote 
Calibration 
If  the IEEE-488 Interface is installed,  the 8840A can 
be 
calibrated under remote control. Remote calibration is very 
similar to local (front-panel  controlled) calibration. Table 
6-14 shows the remote commands which 
correswnd to the 
- 
- 
ENABLE 
switch.  fiont  panel  features. 
Figure 
69. 
Optimizing 
Use 
of  the 
5450A 
INPUT 
HI 
SENSE 
HI 
INPUT LO  SENSE LO 
Table 
6-14. 
Commands  Used During Remote Calibration 
t 
0 
OUTPUT 
HI 
SENSE HI 
OUTPUTLO  SENSEBO 
J 
8MOA 
5450A 
FRONT 
PANEL 
FEATURE 
Range 
--- 
D~splay 
Function 
Buttons 
STORE 
CORRESPONDING 
COMMAND 
R1 
through 
R6 
COMMENTS 
-- 
- 
- 
- 
-- 
- 
G2 
F1 
through 
F6 
In  the  calibration  mode,  these  select  the  Offset  and 
Gain  Calibration 
procedure for the corresponding range in 
the 
presently selected function. 
(For entering variable  inputs, 
see 
VAR 
IN 
below.) 
Tells the 
8840A 
that the requested calibration input 
is 
valid. This command 
causes the 
8840A 
to 
take  readings, and compute and store calibration 
constants. 
-- 
- 
- 
- 
-- 
- 
- 
- 
- 
- 
- 
- 
Loads the  calibration  prompt  into the  output buffer.  Not  valid  when  the 
8840A 
is 
taking  verification  readings. 
In  the  calibration 
procedure for the  corresponding function. 
NOTE 
The CO  and C3 commands can take 
up 
to 
22 
sec- 
onds to  execute. You  must  determine when  these 
commands are complete before sending more 
com- 
mands. See Timing  Considerations in  text. 
AID 
C 
1 
Selects the 
ND 
Calibration  procedure. 
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