Hanna Instruments HI 504901 - Manual (Page 27)

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POWER FAILURE
The power failure status is the working mode of HI504901
when the mains power supply fails and the interface works
using the internal backup battery.
In this situation the green “SMS enable” and red “SMS dis-
able” LEDs are in the following conditions:
LED Status Meaning
SMS enable (green) blinking SMS sending enabled
SMS disable (red) OFF
SMS enable (green) OFF SMS sending disabled
SMS disable (red) blinking
All other LEDs (excluding the digital output LED when the
digital output contact is closed) are turned off.
If the SMS sending is user enabled, then alarm SMS related
to power failure event will be sent by HI504901 to the pro-
grammed number(s) (see “SMS delivery” section).
After that, if
1. sending of maximum number of repeated messages is
reached without user confirmation, or
2. HI504901 receives a phone call from one of the pro-
grammed number(s) to confirm alarm SMS reception, or
3. SMS sending is disabled through external switch,
then HI504901 turns off the cellular phone engine to pre-
vent internal backup battery consumption.
Note If SMS sending was disabled before power supply failure event,
then cellular phone is immediately turned off and no alarm
will be issued by interface.
While in power failure status HI504901 does not perform
device polling procedure, so that new alarms on instruments
connected to the interface can not be notified.
Also interface configuration and PC communications (both lo-
cal & remote) are not allowed until mains supply comes back.
When the mains power supply comes back, the cellular phone
turns on and cellular initialization procedure takes place (it
keeps about 30 seconds). As in start-up procedure, during
cellular phone initialization the red LED for SMS disable turns
on while the green LED (SMS enable) turns off. When cellular
phone is ready, HI504901 sends the SMS “Power is OK now!”
to the programmed number(s), if SMS sending is enabled.
LEDs STATUS DURING PC COMMUNICATION SESSION
Following is a table with all possible status of HI504901 LEDs
during a PC communication session:
LED Status Meaning
RS232 channel # (red)
RS485 channel (red)
Digital input (red)
SMS enable (green)
SMS enable (red)
Digital output (yellow)
Cell signal quality
(2 green LEDs)
Cell status (yellow)
OFF PC communication in progress with
another channel or not yet channel
selection made by remote PC
Blinking Communication session in progress
between remote PC and this channel
OFF PC communication in progress with
another channel or not yet channel
selection made by remote PC
Blinking Communication session in progress
between remote PC and one RS485
instrument
OFF --- (no meaning)
OFF --- (no meaning)
ON --- (no meaning)
ON / OFF Indication about digital output
previous status (ON if contact closed,
OFF if contact open)
both OFF, or Indication about last cellular signal
ON + OFF, or strength before PC communication
both ON session beginning
ON / OFF / blinking Cellular phone real time operating
status (fast blinking if remote
communication is taking place)