Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual page 1005

Basic I/O Unit Instructions
Flags
Precautions
966
Name Label
Error Flag ER
Equals Flag =
The Equals Flag will turn ON if the reading operation is completed normally.
The Equals Flag will turn OFF if the reading operation cannot be completed
normally due to the Special I/O Unit or CPU Bus Unit being busy.
Whenever any of the following occur, an error will occur and the Error Flag will
turn ON.
• The number of words to transfer (S) is outside the range of 0001 to 0080
(hex).
• The unit number (S) is outside the range of 0000 to 005F hex or 8000 to
800F hex.
• The designated Special I/O Unit is on SYSMAC BUS.
• A Special I/O Unit or CPU Bus Unit not affected by IORD(222) is desig-
nated.
• A Special I/O Unit with a Special I/O Unit setting error or a Special I/O
Unit error is designated.
• A CPU Bus Unit with a CPU Bus Unit setting error or a CPU Bus Unit
error is designated.
When IORD(222) is executed, the execution results are reflected in the condi-
tion flags. In particular, the Equals Flag turns ON when reading is completed.
Input the condition flags such as the Equals Flag with output branching from
the same input conditions as the IORD(222) instruction.
If the Special I/O Unit or CPU Bus Unit is busy, the reading operation will not
be executed. Use the Equals Flag to create a self-maintaining program, as
shown below, so that IORD(222) will be executed with each cycle until the
reading operation is executed.
Operation
ON if the number of words to transfer (S) is outside the
range of 0001 to 0080 hex.
ON if the unit number (S) is outside the range of 0000 to
005F hex or 8000 to 800F hex.
ON if the designated Special I/O Unit is on SYSMAC
BUS.
ON if a Special I/O Unit or CPU Bus Unit not affected by
IORD(222) is designated.
ON if a Special I/O Unit with a Special I/O Unit setting
error or a Special I/O Unit error is designated.
ON if a CPU Bus Unit with a CPU Bus Unit setting error or
a CPU Bus Unit error is designated.
With the CS1D CPU Units: ON if the active and standby
CPU Units could not be synchronized.
OFF in all other cases.
ON if reading operation is completed normally.
OFF if reading operation is not completed normally.
Section 3-23