ensuring that itis not lost or forgotten. If necessary the passcode can be re-
stored by contacting themanufacturer. To enter the passcode use the Up and
Downbuttons to set each digit of the passcode and the ENT butto n to move to
the next digit on the right. Press ENT twice when all digits are entered to move
to the nextf unction. If the passcode is entered correctly the next function in the
CAL Modewill appear.
7.8.5 Date
This functiondisplays the present date and allows it to be changed. This func-
tion is placed in the passcode protected partof the CAL Mode since the calibra-
tion duewarning messages depend on the present date as well as the stored due
dates. Use theUp and Down buttons to set each date segment and the ENT
button to movebetween the d ate segments.Press ENT when all digits are en-
tered tosave the changed values. The CLR button moves to the next function.
7.8.6 Probe Lock
This functionlocks or unlocks operation of the unit with the presently co n-
nected probe only.If probe lock is set to ON, the instrument can only be used
to display temperature with the probe attached when probe lock was set ON. If
probe lock is ON and a different probe is attached the instrument will display
the serialnumber of the connected probe, ‘PRT: xxxxxxxxxx’, and then the
message “Probe is locked”.Measuring will be disabled. If probe lock is OFF
the instrumentcan be used with any probe. To lock the instrument with a new
probe, setprobe lock OFF, attach the new probe, and then set probe lock ON
again. Probelock ON also disables access to the probe parameters that follow
in the menu. The probe parameters, beginning with theprobe serial number,
willonly appear in the menu if probe lock is OFF. To set probe lock use the Up
and Downbuttons to select ON or OFF and press the ENT button to store and
continue.
7.8.7 Prb #
This functiondisplays the serial number of the probe and allows it to be set.
The probeserial number is stored in the INFO-CON probe connector. Use
the Up and Downbuttons to set each digit and the ENT button to move to the
nextdigit on the right. Press ENT when all digits are entered.
7.8.8 Prb Type
This functionspecifies the type of probe and its characterization. It allows the
1521 to use the appropriatealgorithm to calculate temperature from the mea-
sured resistanceof the probe. The functions that follow the probe conversion
function for setting probe characterization coefficients depend on the selected
probe type. Thetable below lists the probe types and the corresponding
coefficients.
ProbeType Description Coefficients
31
7 Display Functions
CAL MODE