Honeywell ISA100 Gen X User Manual page 55

Alert priority helps to prioritize alerts when multiple alerts occur at the same time and
prioritize the one to be sent first.
A value is associated with each alert to indicate the value related to that alert. For example,
a battery low voltage alarm can carry the current battery voltage in the alert, and so on.
Alarm Regeneration
This is a separate functionality to recover the active alarms in the Sensor. This message is sent
when the system manager requests an alarm regeneration if it loses all the alarms by database
corruption. The alarm regeneration request comes as a stack packet and sets the UAPMO
variable uapmovar.alert_regen. The function uapmo_alert, which gets called every 1 second,
checks all the alarms in the alert descriptor table for active alarms and sends the corresponding
alarm messages. When all the messages are transmitted, it sends the stack message
ISA100_NOTIFY_ALARM_REGEN_END.
IR Communication Interface
IR Communication interface works at 9600 baud rate. The IR communication is implemented
using Timer A for bit detection and generation. The IR interface is designed to normally operate
in a very low power listen mode where it turns off the IR transceiver and wakes every 1 second
and enables the IR receiver for 3.5 character times to listen for a wakeup bit stream. Detection
of 2 pulses in 3.5 character times is taken as a valid wakeup pulse and puts the micro in LPM1
mode so that the SM clock is running, and further data can be successfully received. If less than
2 pulses are detected within 3.5 characters, then it is treated as no communication is happening
on the IR port and IR port is power down. If a wakeup bit stream (> 2 pulses) is detected, the IR
interface goes to the receive mode. When in receive mode, the interface remains in the receive
mode for a 10 second time-out or with no incoming data. If an incoming data is received within
10 seconds time-out, the time-out is reinitialized back to 10 seconds. Once the 10 second time-
out has occurred without receiving any incoming data for 10-seconds, the IR driver returns to
low power listen-mode where the IR transceiver is switched off. 0x C0 is the synchronization
byte for reception and transmission. A train of 1000 FFs are used for waking up the device from
sleep.
A total of 10 bits is transmitted for a byte. Start bit is always 0 and the Stop bit is 1. "0" is
represented by a pulse of the duty cycle 3/16 and "1" is represented by the absence of a pulse.
Release Independent
April 2018
REFERENCE -EXTERNAL
For details about IR physical layer and communication details, refer WCI
ISA100.11a Out of Band Provisioning Specification document.
ISA100 Gen X Radio Module User's Guide
Honeywell
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