Gasboy CFN Series Diagnostic Manual - Manual (Page 59)

Site Controller I
0021 2-33
No Island Loop communications. All devices on Island Loop are down.
Possible Cause Checks Corrective Action
Site controller is down. Check logger or do a PRint
DIagnostics command for
indication that the site is not
running. Do a RUN command if site is
down.
RS-485 phone cable is loose
or not installed correctly. Check that one end of the
cable is installed in the
junction box and the other
end is installed in the PCU/RT
connector on the rear of the
Site Controller I. Install cable properly if it is
incorrect
Incorrect wiring of junction
box or island loop devices. Verify all field wiring with the
SC I Installation Manual
(C01917). Make wiring connections if
needed.
Defective RS-485 receiver IC
and Protected Driver Board. None. Replace U2 and U3 on the
SC I CPU Board. When
replacing U3, replace the
entire Protected Driver Board
(C05848), not just the driver
IC.
Verify that the junction box is
properly grounded as shown
in the SC I Installation
Manual.
Defective CPU Board. None Replace the SC I CPU Board
Defective RS-485 junction
board. None. Replace the RS-485 junction
box