ensuring that it is not lost or forgotten. If necessary the passcode can be re
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stored by contacting the manufacturer. To enter the passcode use the Up and
Down buttons to set each digit of the passcode and the ENT button to move to
the next digit on the right. Press ENT twice when all digits are entered to move
to the next function. If the passcode is entered correctly the next function in the
CAL Mode will appear.
7.8.5 Date
This function displays the present date and allows it to be changed. This func
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tion is placed in the passcode protected part of the CAL Mode since the calibra
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tion due warning messages depend on the present date as well as the stored due
dates. Use the Up and Down buttons to set each date segment and the ENT
button to move between the date segments. Press ENT when all digits are en
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tered to save the changed values. The CLR button moves to the next function.
7.8.6 Probe Lock
This function locks or unlocks operation of the unit with the presently con-
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 serial number of the connected probe, ‘PRT: xxxxxxxxxx’, and then the
message “Probe is locked”. Measuring will be disabled. If probe lock is OFF
the instrument can be used with any probe. To lock the instrument with a new
probe, set probe lock OFF, attach the new probe, and then set probe lock ON
again. Probe lock ON also disables access to the probe parameters that follow
in the menu. The probe parameters, beginning with the probe serial number,
will only appear in the menu if probe lock is OFF. To set probe lock use the Up
and Down buttons to select ON or OFF and press the ENT button to store and
continue.
7.8.7 Prb #
This function displays the serial number of the probe and allows it to be set.
The probe serial number is stored in the INFO-CON probe connector. Use
the Up and Down buttons to set each digit and the ENT button to move to the
next digit on the right. Press ENT when all digits are entered.
7.8.8 Prb Type
This function specifies the type of probe and its characterization. It allows the
1521 to use the appropriate algorithm to calculate temperature from the mea
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sured resistance of the probe. The functions that follow the probe conversion
function for setting probe characterization coefficients depend on the selected
probe type. The table below lists the probe types and the corresponding
coefficients.
Probe Type Description Coefficients
31
7 Display Functions
CAL MODE
