Garnet SeeLevel Special 808-P2 Important Operator Information page 26

6. Starting at the 0 inch value of volume calibration, use the 0 to 9,
decimal, E, F, L, U, or BL buttons on the keypad to enter the calibration.
Press the ENTER button to store the value in memory. When ENTER
is pressed, the inches will go to the next value. If you make a mistake,
use the BACK button to erase the entry, or if ENTER has already been
pressed, use INCHES  to go back to that inch value and re-enter the
correct value. If more than 4 numbers are entered the previous ones
will scroll off the left of the display. If ENTER is pressed before any
numbers, nothing will happen.
7. After the table has been entered, use the INCHES buttons to review
the table to make sure it is correct. If a calibration value is incorrect,
simply re-enter it and press ENTER.
8. Continue with the same procedure as in Program the gauge display
into inches from step 5. When setting the bottom reading, use the
calibration table to look up the volume corresponding to the distance
to the middle of the float. Use the OFFSET buttons to obtain this
reading on the CALIBRATION display.
Page 26 808-P2 Manual