HP 3457A - Page 120

Calibration
3457A
5-9.
In
the
event
that
the
security
code
is
unknown,
the
security
feature
can
be
disabled
to
permit
a
new
code
to
be
entered.
To
disable
the
security
feature,
complete
the
following
steps.
a. Remove all power from the 3457A (line cord and external inputs) and turn the unit upside-down.
b. Loosen the six captive screws in the bottom cover. (It is not necessary to remove these screws from the bot-
tom cover).
c. Return the unit to an upright position and remove the top cover.
d. Remove the NORM / DSA / KEY jumper (JM532) from the NORM position and place it in the KEY
position. (JM532 is located on the AI logic board directly behind the front panel display ).
e. Reconnect the power and turn the instrument ON.
f. Access the SECURE command. (Press the Blue SHIFT key then the RECALL / S configuration key, Use the
| scroll key to display the SECURE command ).
g. Enter the number 0, the delimiter (, ) and the security number you wish to use.
h, Press the ENT key.
i, Disconnect power and return jumper JM532 to the NORM position.
j. Replace the top cover, tighten the retaining screws and reconnect the power. The instrument will
now respond to the security code just entered,
When jumper JM532 is in the KEY position, the security feature is disabled. It is
possible to calibrate the instrument without entering a security number under these
conditions, If a new security number is not entered while the jumper is in the KEY
position, the original number will again be in effect when jumper JM 532 is return-
ed to the NORM position.
5-10, Calibration Number (CALNUM?)
5-11. The CALNUM? command provides you with a method of monitoring the number of calibrations per-
formed. By using this command, you can determine whether un-authorized calibrations have occurred. The
instrument will always respond the CALNUM query command by displaying the number of calibration
RAM entries completed since factory initialization. factory initialization. The maximum calibration num-
ber which can be stored is 32767. After reaching the maximum number, the counter resets to 0 and begins
again, Please note that the calibration number is increased by one for each calibration point. A complete
calibration increases the calibration number by several digits.
5-12, The procedure for reading the Calibration Number is as follows:
a. Access the CALNUM? command. (Press the Blue SHIFT key then the OFFSET COMP / C configuration key.
Use the | scroll key to display the CALNUM? command).
b. Press the ENT key.
5-2