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52
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 uncalibrated 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 required, the “no CAL”
message is displayed if no calibration procedure was per-
formed.
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.
“03<STX>10.7D<ETX>”
meaning that the current temperature reading is 10.7°C, the
control action is active and no alarm condition is present
and controller setup is modified (must update controller setup
for PC – GET commands for setup items).
If asking for the last calibration data and the controller was
never calibrated, it answers with “0”; e.g
.
“01<STX>0<ETX>”.
If the controller was calibrated, it answers with “1” followed
by the calibration data. The Data field of the answer has
the following format:
1<Date><Time><Cell Constant>
• Date:
DDMMYY (e.g. “170400” for April
17,2000)
• Time:
HHMM (e.g. “1623” for 4:23 pm)
• Cell Constant: ASCII string (e.g. “1200”)
The items in the Data field are separated by blanks.
