Start-Up - Hanna Instruments HI21 Series Instruction Manual

START-UP

At start-up the firmware release code scrolls through the
LCD; it is possible to escape from code scrolling pressing
any key.
During the automatic start-up the Real Time Clock (RTC)
is checked to see if a reset occurred since last software
initialization. In this case, the RTC is initialized with the
default date and time 01/01/1997 - 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
checksum test is performed (the same is performed during
EEPROM selftest procedure).
If checksum is correct, normal mode is entered, otherwise
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 pH calibration (pH
models) or mV calibration (mV mod-
els) is needed by means a blinking
"CAL" icon.
When the last calibration data is
required, the "no CAL" message is
displayed if no calibration procedure
was performed.
Unlike pH and mV calibration, user has no information
on calibration need for other magnitudes, 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.
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