NX12
Micro GSM RTU
© Nortech Management Ltd, United Kingdom
Page 13 of 25
5
NX12 RTU Operation
5.1
Cold Start
The RTU is configured to monitor for a processor power-up event, occurring after
periods without mains and battery back-
up power. This is known as a “Cold Start”.
The RTU will then initiate communication with the iHost system.
5.2
LED Indicators
The processor LEDs are used to indicate both the operational state and the
communication state of the RTU.
Diagnostic LED
Condition
Meaning
LED1 (top)
Steady Flashing
Processor working.
LED1
On for 5 seconds
Communication to host successfully
completed.
LED1
Quick Flash
TX Host/Modem Data.
LED2
Steady Flashing
Last communication failed. In retry
sequence.
LED2
On for 5 seconds
Communication to host failed.
LED2
Quick Flash
RX Host/Modem Data.
LED3
Quick Flash
RS485 TX Data.
LED4
Quick Flash
RS485 RX Data.
Led 5 (bottom)
various
Driven directly by the modem.
5.3
RTU connection to the iHost system
The NX12 RTU connects to the iHost system when:
▪
An event that is configured to initiate a connection occurs.
▪
T
he “Next Routine Call” date/time is reached or exceeded.
▪
The user presses the test button (PCB identifier SW1).
A configurable “Routine
Health Check Interval” is configured by the iHost system.
Typically, this is set between 1 hour and 3 hours, however the range for the
interval setting is from 1 minute to 28 days.
An event configured to cause an immediate communication to the iHost system will
do so regardless of when the next routine health check is due.
5.4
Call Retry Algorithm
If a connection to the iHost system fails, then the RTU enters its retry sequence.
The RTU retries in a block of 10 attempts, approximately 1 minute apart. Then it
waits a (re)configurable time before starting another block of 10 attempts. This
repeats until communications is restored.
During this period, if any new events configured as “Immediate Contact Host”
occur, then the RTU will immediately start attempting to contact the iHost system.
