Omron C200H-LK401 ユーザーズマニュアル

Error conditions are indicated by the LEDs as described below.

Some errors in switch settings (e.g., setting the same unit number for more
than on PC Link Unit) will not result in an error display, but will cause LR area
data to be in error.

Only possible on the polling unit: indicates that none of
the PC Link Units are capable of data exchange.

Indicates an error exists in another PC Link Unit that is
not the polling unit.

Indicates an error exists between this Unit and the polling
unit.

Indicates data exchange is not occurring with any other
PC Link Unit.

Indicates all PC Link Units in this operating level are 
exchanging data normally.

Note: Open circles indicate lit LEDs. Half-back circles indicate flashing LEDs.

Indicates setting of PC Link Unit numbers is wrong.