41
STARTUP
During the automatic startup the Real Time Clock (RTC) is
checked to see if a reset occurred since last software initial-
ization. In this case, the RTC is initialized with the default
date and time 01/01/1998 - 00:00. An EEPROM reset does
not affect the RTC settings.
The EEPROM is also checked to see if it is new. If this is the
case, the default values are copied from ROM and then the
device enters normal mode. Otherwise an EEPROM check-
sum test is performed (the same is performed during EEPROM
selftest procedure).
If checksum is correct, normal mode is entered, otherwise the
user is asked whether the EEPROM should be reset.
If EEPROM reset is requested, default values from ROM are
stored into EEPROM as would happen with a new EEPROM.
Note that EEPROM data is composed of setup data and
calibration data. As for the setup data, the calibration data is
assigned default values when an EEPROM reset occurs. An
un-calibrated meter can perform measurement, though user
is informed that EC or TDS calibration is needed by means of
a blinking “CAL”.
When the last calibration data is re-
quired, the “no CAL” message is
displayed if no calibration procedure
was performed.
Unlike EC/TDS calibration, the user has no information on
calibration need for other ranges, other than the awareness
that EEPROM was reset.
After an EEPROM reset, all calibrations (input and output)
have to be performed in order to obtain correct measure-
ments.
