25
September 2015
Responses from Sat: Indicates the number of responses the MIM/TWI heard back from the
channel after being called. A low number or a zero indicates that either the
controller is not responding or the MIM/TWI is not hearing the response.
Total Calls Heard:
This number indicates the total number of calls the channel heard from the
MIM/TWI. This is compiled by the controller and downloaded to the
MIM/TWI after it requested it. The MIM/TWI asks for this data once per
hour, on the odd minutes, based on a defined schedule (ex.: Group 1,
channels 1 to 14 is requested at the 3
rd
minute after the hour, channels 15
to 28 at the 11
th
minute after the hour, etc.)
Total Days:
This indicates the number of days the system has recorded since the log
was cleared.
System Availability: This percentage is an expression of the time available for communication
for the MIM/TWI. It is an important indicator of interference with LINK
communication. As an example, a value of 90% in Location column #14
(remember that the “Location” row indicate the hour of the day when
looking at the System Availability row) means that the system could not
transmit for 10% of the time (6 minutes) between 1 and 2 PM. This row
allows pinpointing the time of the day an interference problem is occurring.
Examples of Link Quality issues:
If Channel 3 had 246 Calls to Sat, 130 Responses, and 124 Total Calls heard - Problem would be
receiving.
If Channel 3 had 246 Calls to Sat, 130 Responses, and 224 Total Calls heard - Problem would be
in Satellite Transmit
If Channel 3 had 246 Calls to Sat, 120 Responses, and 172 Total Calls heard - Could be a range
problem (70% each way).
1.
Basic Troubleshooting
On a LINK system, it is important to address communication issues promptly. As few as
three non-responding channels can cause important communication issues with the rest
of the controllers since the system is always trying to reach the non-communicating
channels.
When first programming the central control and adding controllers, it is important to only
add channels to the database as they are actually installed in the field. If a controller
must be programmed prior to install, make sure to render the controller inactive in the
satellite definition screen until it is installed.
•
Is the issue affecting multiple channels / controllers?
o
Are these controllers getting their signal directly from the MIM/TWI or
through a repeating controller?
If from MIM/TWI, could be related to a “general” issue, like MIM
antenna, cables, etc. especially if the issue affects the furthest
controllers
If these units are getting their signal from a single repeating
controller, the issue is most likely at that unit
o
Is the System Availability above 98% at all hours?