Omron CJ - 08-2008 Operation Manual page 573

Troubleshooting Racks and Units
CJ Long-distance Expansion Racks
Symptom
CPU Unit won't operate. (No
response to Programming
Devices and no CPU Unit
indicators are lit.)
Expansion Rack not
detected.
I/O bus error or I/O verifica-
tion error occurs.
Cycle time is too long.
I/O Control Unit and I/O Inter-
face Units do not appear on
CX-Programmer I/O table.
Cause
(1) Power is not turned ON to an Expansion
Rack.
(2) An Expansion Rack is not connected
correctly.
(3) An I/O Connecting Cable is not wired
correctly.
(4) A Unit is faulty.
(1) A Terminator is not connected.
(2) An Expansion Rack is not connected
correctly.
(3) A Unit is faulty.
(1) An I/O Connecting Cable or Terminator
connection is faulty.
(2) Expansion cable is not wired correctly
(3) Noise or other external factor.
(4) A Unit is faulty.
(1) A CPU Bus Unit that is allocated many
words (e.g., Controller Link Unit) is
mounted to a CJ Long-distance Expan-
sion Rack.
(2) A Unit is faulty.
This is not an error. These Units are not allo-
cated I/O words and thus are not registered
in the I/O tables.
Remedy
Turn ON power to all Expansion Racks.
Recheck the connections and configuration
using information in 2-3-3 CJ-series Expan-
sion Racks, 3-5 I/O Control Units and I/O
Interface Units.
Reconnect the I/O Connecting Cables in the
correct order for output and input connec-
tors.
Gradually remove/replace Units to deter-
mine the Unit that is faulty, including the
Power Supply Unit, I/O Units, I/O Control/
Interface Unit, and I/O Connecting Cable.
If the TERM indicator is lit, connect a Termi-
nator.
Recheck the connections and configuration
using information in 2-3-3 CJ-series Expan-
sion Racks, 3-5 I/O Control Units and I/O
Interface Units.
Gradually remove/replace Units to deter-
mine the Unit that is faulty, including the
Power Supply Unit, I/O Units, I/O Control/
Interface Unit, and I/O Connecting Cable.
Check that I/O Connecting Cables and Ter-
minators are connected correctly.
Rewire the terminals using the correct OUT-
IN sequence.
Separate all cables from possible sources of
noise or place them in metal ducts.
Gradually remove/replace Units to deter-
mine the Unit that is faulty, including the
Power Supply Unit, I/O Units, I/O Control/
Interface Unit, and I/O Connecting Cable.
Move the CPU Bus Unit to the CPU Rack.
Gradually remove/replace Units to deter-
mine the Unit that is faulty, including the
Power Supply Unit, I/O Units, I/O Control/
Interface Unit, and I/O Connecting Cable.
---
Section 11-3
525