Hanna Instruments mV 602 Series - Manual (Page 28)

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RELAYS AND LEDS
Relays and LEDs selftests are executed as follows:
First all of the relays and LEDs are switched off, then they are
switched on one at a time for a few seconds and cyclically.
User can interrupt the otherwise endless cycle, as indicated
by the scrolling message, by pressing a key.
Note Relays and LEDs test has to be carried out with the relay
contacts disconnected from external plant devices.
WATCHDOG
When a dead loop condition is detected a reset is automati-
cally invoked.
The effectiveness of watchdog capability can be tested through
one of the special setup items. This test consists of executing
a dummy dead loop that causes watchdog reset signal to be
generated.
The colon is a useful indicator for the correct position of
squares.
Note A maximum of two keys may be pressed simultaneously to be
properly recognized.
To exit the keyboard test procedure press LCD, CAL and SETUP
simultaneously.
EEPROM SELFTEST
The EEPROM selftest procedure involves verifying the stored
EEPROM checksum. If the checksum is correct the “Stored
data good” message will be shown for a few seconds before
exiting selftest procedure.
If not, the message “Stored data error - Press to reset
stored data or to ignore”.
If is pressed the EEPROM selftest procedure terminates
with no other action. Otherwise, EEPROM is reset with de-
fault values from ROM as when a device with a virgin
EEPROM is switched on.
During EEPROM reset a blinking mes-
sage “Set MEM” is shown on the LCD.
At the end of this operation all the pa-
rameters are reset to their default
values. Calibration data is also reset.
For this reason the "CAL" flag blinks
until the pH calibration is performed.