Franklin Fueling Systems TS-DTU Noise Suppression Cables TS-DRK - Manual (Page 2)

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Overview
Reports indicate that at a few ISD installations, equipment
such as canopy and cooler lights can generate excessive
electrical noise that affects the DTU communications
quality. Franklin Fueling Systems has developed a
new series power cable for the TS-DTU that has noise
suppression capabilities. These CARB-approved cables,
for use with the “Remote” DTUs installed in the dispensers,
contain ferrite beads that suppress the noise while still
allowing the data to pass. Most installations function
normally with the standard cables included with the current
TS-DRK Dispenser Retrofit Kits and future TS-DRK will
also contain these new cables.
This guide will help determine if installation of the noise
suppression power cables will resolve an issue you might
be experiencing. It will also provide installation instructions.
This assumes that the Console DTU has established
communication with the Remote DTUs but quality is low,
and many DTU alarms have been generated as a result.
Identifying the Situation
Explanation of a “Remote DTU is Offline” alarm
A “Remote DTU is Offline” alarm is generated when the
Console DTU does not get a complete communication
response from the Remote DTU after a period of up to two
minutes. The alarm will clear when the communication
response has been reestablished.
An incomplete or no response from the Remote DTU can
be caused by a few things and does not always indicate a
communication problem. Further explanation is discussed
in Alarms Examples of this document.
1. Dispenser is powered down. A Remote DTU
is powered from the dispenser power. If the
dispenser was powered down for any reason it
will result in a “Remote DTU is Offline” alarm. See
Figure 1.
Figure 1: Example of Dispenser 1 (Remote 1 DTU) Shutdown
2. Console DTU is powered down or disconnected
from the Console. The Console DTU transfers the
Remote DTU data to the console. If this Console
DTU loses communication either due to being
powered down or disconnects from the bus, then
all the Remote DTUs will issue the “Remote DTU
is Offline” alarm. In conjunction, you should also
see a “Console DTU Module Mismatch” alarm.
See Figure 2
Figure 2 - Console DTU powered down or lost
communication
3. Remote signal strength is not strong enough. If
the Remote DTU signal has be attenuated (loses
strength) then the Console DTU may not be
able to reliably read the incoming data. This is a
common issue when there are power line filters
installed inside the dispenser as they try and filter
the signals as if it was noise. See Figure 3.
Figure 3 - Power Line Filter loading DTU signal