Fatal Errors In The Cpu Unit; Types Of Fatal Errors; Checking For Fatal Errors - Omron NJ501-1 Series User Manual

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Fatal Errors in the CPU Unit

Types of Fatal Errors

Some errors are fatal and prevent the CPU Unit from operating. This section describes the errors that
cause the operation of the CPU Unit to stop. The Sysmac Studio and NS-series PTs cannot connect
communications if a fatal error occurs.
 Power Supply Error
Power is not supplied, the voltage is outside of the allowed range, or the Power Supply Unit is faulty.
 CPU Unit Reset
The CPU Unit stopped operation because of a hardware error. Other than hardware failures, this
error also occurs at the following times.
• The power supply to an Expansion Rack is OFF.
• The I/O Connecting Cable is incorrectly installed.
• The IN and OUT connectors are reversed.
• The connectors are not mated properly.
• There is more than one I/O Control Unit on the CPU Rack or there is an I/O Control Unit on an
Expansion Rack.
 Incorrect Power Supply Unit Connected
There is a CJ-series Power Supply Unit connected to the CPU Rack. The operation of the Controller
is stopped.
 CPU Unit Watchdog Timer Error
This error occurs in the CPU Unit. This error occurs when the watchdog timer times out because of
a hardware failure or when temporary data corruption causes the CPU Unit to hang.

Checking for Fatal Errors

You can identify fatal errors based on the status of the PWR indicator on the Power Supply Unit and the
RUN and ERROR indicators on the CPU Unit, as well as by the ability to connect communications to
the Sysmac Studio.
PWR (green)
Not lit Not lit
Lit Not lit
Lit Flashing (3-s intervals) Lit
Lit Not lit
* Power Supply Errors and Incorrect Power Supply Unit Connected errors can be differentiated with the indicators. There is
no need to check communications with the Sysmac Studio.
NJ-series CPU Unit Hardware User's Manual (W500)
Indicator
RUN (green) ERROR (red)
Not lit
Not lit
Lit
5 Troubleshooting
Communications CPU Unit operating
with Sysmac Studio
Not possible.* Power Supply Error
CPU Unit Reset
Incorrect Power Sup-
ply Unit Connected
CPU Unit Watchdog
Timer Error
5
status
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