Application Precautions - Omron WS02-LCTC1-E - V2.60 REV 12-2003 Manual

Application Precautions

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4 Application Precautions
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Before transferring function block data (initial setting data or operation data) to
the Loop Control Unit, confirm that the destination for the data is correct and also
confirm the overall safety of the system (including the Loop Control Unit). Not
doing so may result in unexpected operation.
Observe the following precautions when using CX-Process Tool.
Loop Control Unit data is monitored and operated using CX-Process Monitor
based on the monitor tag files created using CX-Process Tool. CX-Process Tool
can be used on Microsoft Windows 95, 98, Me, 2000, or NT (Service Pack 4 or
later). When creating monitor tag files using CX-Process Tool, CX-Process
Monitor must be installed on the same computer.
Before using function block data in actual operation, confirm operation by moni-
toring run status (to check the load rate; select Execute/Operation/Monitor
Run Status) and validating actions (select Validate Action/Start) with CX-Pro-
cess Tool. In particular, be sure to confirm that the load rate will be less than 60%.
(For details on the load rate, refer to the Loop Control Unit Operation Manual.)
The Loop Control Unit can read and write I/O memory in the CPU Unit using the
Field Terminal Function Blocks or CPU Terminal Blocks independent of the user
program (Step Ladder Program) in the CPU Unit. Do not write to the same I/O
memory words from both the Loop Control Unit and the CPU Unit.
To hold an analog output or contact output at a specific value (for example, the
maximum value or minimum value) when the Loop Control Unit stops running,
create a Step Ladder Program in the CPU Unit so that the corresponding output
bit allocated to Analog Output Unit or Contact Output Unit is set to the desired
value using an NC condition of the Loop Control Unit Running Flag (bit 00 in allo-
cated CIO word "n") as an input condition.
If a fatal error occurs in the CPU Unit (including fatal errors created by execution
of an FALS instruction), the Loop Control Unit will also stop running. To hold ana-
log outputs to the previous values before the stop occurred, and to set analog
outputs to either the minimum value or maximum value, use the output hold
function of the Analog Output Unit or Analog I/O Unit.
Before turning ON the power to the PLC, make sure that the facilities are safe.
The analog output values and contact outputs from the Loop Control Unit are
updated when the power to the PLC is turned ON regardless of the operating
mode of the CPU Unit (including in the PROGRAM mode). (Internally, the analog
output values and contact outputs are sent from the CPU Unit to Basic I/O Units
and Analog Output Units.)
Fail-safe measures must be taken by the customer to ensure safety in the event
of incorrect, missing, or abnormal signals caused by broken signal lines, mo-
mentary power interruptions, or other causes.
Confirm that no adverse effect will occur in the system before attempting any of
the following:
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