Hanna Instruments HI 504901 - Manual (Page 10)

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IDLE STATE
The idle state is the normal operation state for the HI504901
supervisor. While in idle state, the following main tasks are
fulfilled:
• Management of incoming remote connection and con-
figuration requests (see “Interface configuration” and “PC
communication” sections for details);
• Management of incoming local connection and configu-
ration requests;
• Polling procedure of connected devices;
• Diagnostic selftest procedures: battery test, cellular phone
test, EEPROM corruption data test (see “Fault condition”
and “SMS delivery” sections);
• Processing of incoming SMS’s for digital output control (if
enabled) and information SMS’s request (see “SMS deliv-
ery” section);
• Sending of alarm SMS’s or information SMS’s upon user
request (see “SMS delivery” section).
When in idle state, the HI504901 can perform periodically
some diagnostic selftest procedures as: internal backup bat-
tery test, cellular phone test, EEPROM corruption data test. If
one of these tests does not pass, the interface advises the
user with a visual indication about the problem using the red
and green SMS enable/disable LED’s. Please refer to “Fault
conditions and Selftest Procedures” section for more com-
plete indications about interface related fault conditions.
Moreover, every 30 seconds the two green LED’s for cellular
phone signal are updated with the current signal strength,
and the indication meanings are listed in the table below:
LED Status Meaning
Cell Signal 1 (green) OFF No signal or
Cell Signal 2 (green) OFF cellular error found
Cell Signal 1 (green) ON Medium signal
Cell Signal 2 (green) OFF
Cell Signal 1 (green) ON Strong signal
Cell Signal 2 (green) ON
START-UP
Turn ON the power switch (#14
on page 8): the red SMS disable
LED lights up and will stay in this
state until the start-up procedure
ended and the idle mode is en-
tered.
During start-up procedure the Real Time Clock (RTC) is
checked to control if a reset occurred since last software ini-
tialization. In this case, the RTC is initialized with the default
date and time 01/01/2000 - 00:00. An EEPROM reset does
not affect the RTC settings.
The EEPROM is also checked to control if it is new. In this
case, the default values are copied from ROM and the de-
vice enters normal mode. Otherwise an EEPROM checksum
test is performed (the same is performed periodically during
EEPROM selftest procedure, see “Fault Condition and Selftest
Procedure” section for more details).
If checksum is not correct, the proper EEPROM error LED
indication will be given as soon as the Idle state is entered.
During start-up, the internal cellular phone is turned ON
and an initialization procedure is performed to insert PIN
code (when needed) and make network registration for en-
abling incoming and outcoming calls. Moreover, the
telephone answering service is disabled to avoid automatic
network call forwarding if interface is busy and can not serve
immediately incoming call.
Initialization procedure can last up to 30 seconds if no prob-
lem occurs, otherwise some more time could be needed and
proper cellular LED indication will be given in idle state.
When the start-up procedure is complete, the interface enters
the idle state.
Note When the HI504901 is turned ON for the first time, it is
possible to get a cellular error indication. This can happen if
the SIM card requests a PIN code to be registered in the
network and the interface was not yet configured (see “Local
configuration” section for details).