Delta Controls DZNR-768, Installation Manual

Page: 22 / 28

Diagnostics and troubleshooting
Page 22 of 28 DZNR-768 Revision 1.2 Installation Guide
Document Edition 1.5
Advanced diagnostics
Sometimes a problem that originates on one segment transfers to other segments and cause
the DZNR to give multiple failure indications. When this happens, troubleshooting is more
difficult because the LED patterns vary and it takes additional time to assess the true nature of
the problem.
Segment lockout
The DZNR isolates communications errors to one segment and prevents the errors from
spreading by locking out the problem segment. During this interval, the segment Err LED
turns red and all communications on that port are blocked. After a lockout of 120 seconds, the
DZNR releases the port to see if the errors clear. If the problem persists, the DZNR initiates
another segment lockout.
Troubleshoot complex communications problems
To troubleshoot complex communications problems, disconnect each port connector, one at a
time. Once the problem segment is removed, the other ports on the DZNR clear and return to
normal. Once it is identified, the problem segment can be further subdivided and tested with
the DZNR until the exact failure is isolated and the DZNR verifies that communications have
been fully restored.
Incomplete or broken
network wiring.
Note: If segment LEDs are
yellow or red a different
wiring problem is likely,
such as shorted wiring or
crossed wiring. A break in the network
wiring prevents several
devices from communicating
on the network.
A group of devices using the
same power source are off
line.
Termination devices are
missing or incorrectly
applied