Troubleshooting Racks And Units - Omron SYSMAC CS Series Operation Manual

Troubleshooting Racks and Units

11-3 Troubleshooting Racks and Units
CPU Racks and Standard Expansion Racks
Symptom
POWER indicator is not lit.
RUN output* does not turn ON.
RUN indicator lit.
(*C200HW-PS204R/209R)
Serial Communications Unit or CS-
series CPU Bus Unit does not operate
or malfunctions.
Bits do not operate past a certain point.
Error occurs in units of 8 points.
I/O bit turns ON.
All bits in one Unit do not turn ON.
Special I/O Units
Symptom
The ERH and RUN I/O refreshing is not being performed for the
indicators on the Spe- Unit from the CPU Unit (CPU Unit monitoring
cial I/O Unit are lit. error).
It's possible that cyclic refreshing has been dis-
abled for the Special I/O Unit in the Cyclic
Refresh Disable Setting in the PLC Setup (i.e.,
the bit corresponding to the unit number has
been set to 1).
CS-series Long-distance Expansion Racks
Symptom
CPU Unit won't operate. (No
response to Programming
Devices and no CPU Unit
indicators are lit.)
Cause
PCB short-circuited or damaged.
(1) Error in program.
(2) Power line is faulty.
Internal circuitry of Power Supply Unit
is faulty.
(1) The I/O Connecting Cable is faulty.
(2) The I/O bus is faulty.
Refer to the Operation Manual for the Special I/O Unit to troubleshoot any
other errors.
Cause
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.
Remedy
Replace Power Supply Unit or Back-
plane.
Correct program.
Replace Power Supply Unit.
Replace Power Supply Unit.
Replace the I/O Connecting Cable
Replace the Backplane.
Remedy
Change the bit corresponding to the unit num-
ber to 0 to enable cyclic refreshing, or make
sure that the Unit is refreshed from the program
using IORF at least once every 11 s.
Remedy
Turn ON power to all Expansion Racks.
Recheck the connections and configuration
using information in 2-3-3 Expansion Racks,
3-5-4 I/O Control Units, I/O Interface Units,
and Terminators, and 5-2-7 I/O Connecting
Cables.
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
Backplane, Power Supply Unit, I/O Units,
I/O Control/Interface Unit, and I/O Connect-
ing Cable.
Section 11-3
573