Fault Conditions And Selftest Procedures - Hanna Instruments HI700 Series Instruction Manual

FAULT CONDITIONS AND SELFTEST PROCEDURES

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The fault conditions below may be detected by the software:
• EEPROM data error;
• I2C internal bus failure;
• date lost;
• code dead loop.
EEPROM data error can be detected through EEPROM test procedure at startup or when
explicitly requested using setup menu.
When an EEPROM error is detected, user is given the option to perform a reset of EEPROM.
Note
When an EEPROM reset has been performed calibration data
are reset to default (every range). An intermittent CAL will
blink on the display to advise the user of this status.
A I2C failure is detected when the I2C transmission is not
acknowledged or a bus fault occurs for more than a certain number of attempts (this
can be due, for example, to damage sustained by one of the ICs connected to I2C bus).
If so, the controller stops any tasks and displays a perpetual sliding message "Serial
bus error" (i.e. this is a fatal error).
If an invalid date is read from RTC, it is initialized back to the default date and time
(01/01/98 - 00:00).
The error detection for dead loops is performed by watchdog (see below).
You can use special setup codes, perform selftest procedures for LCD, keyboard, EEPROM,
relays and LEDs, watchdog. The operation of these functions is outlined in the setup
section. The selftest procedures are described in detail in the following subsections.