Omron CJ1G/H-CPU series Operation Manual page 44

CJ-series Features
Failure Point Detection:
FPD(269)
Error Log Functions
Maintenance Functions
Other Functions
Data Trace Function
Fixed Cycle Time Function
I/O Refreshing Methods
Peripheral Servicing
Priority Mode
PLC Setup Functions
Diagnoses a failure in an instruction block by monitoring the time between
execution of FPD(269) and execution of a diagnostic output and finding which
input is preventing an output from being turned ON.
The error log contains the error code and time of occurrence for the most
recent 20 errors (user-defined or system-generated errors).
The CJ-series PLCs record information useful for maintenance, such as the
number of power interruptions and the total PLC ON time.
The content of the specified word or bit in I/O memory can be stored in trace
memory by one of the following methods: scheduled sampling, cyclic sam-
pling, or sampling at execution of TRSM(045).
Specified address
in I/O memory
A fixed (minimum) cycle time can be set to minimize variations in I/O response
times.
I/O refreshing can be performed cyclically and immediately by programming
the immediate-refreshing variation of the instruction.
The CPU Unit can be set to execute peripheral servicing periodically and
more than once in each cycle. Up to five items can be set for priority servicing,
including the RS-232C port, peripheral port, CPU Bus Units, and Special I/O
Units. This feature supports applications that require giving priority to servic-
ing peripheral devices over program execution, such as for host monitoring
systems for process control where response speed is important.
PLC operation can be customized with PLC Setup settings, such as the maxi-
mum cycle time setting (watch cycle time) and the instruction error operation
setting, which determines whether instruction processing errors and access
errors are treated as non-fatal or fatal errors.
FPD
Input preventing
diagnostic output
from going ON
Trace memory
The PLC's initial settings can be
customized with the PLC Setup.
Section 1-2
11