YOKOGAWA F3LR02-0N, User Manual

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C6-12
IM 34M06H45-01E 7th Edition : Aug.30, 2019-00
C6.4 Error Location Detection Function
C6.4.1 LED Display
When an error occurs with the FA-bus Type 2 module, or when a cable discontinuity
occurs in a transmission channel, the error (ERR) LED or alarm (ALM) LED of the CPU
module turns on to report the error.
Table C6.7 Status of
CPU’s LEDs
Status of
CPU’s LED
Condition Setting in Configuration
I/O Module Error
Conditional
Operator
Subunit Communication Error
ALM lit Run AND Run
ERR lit Stop OR Stop
The LEDs of the CPU module turn on even if an error is generated in a module other
than the FA-bus Type 2 module.
To decide whether the cause of a lit LED lies in the FA-bus Type 2 module, check the
status of the RDY, ERR1 (port 1) and ERR2 (port 2) LEDs of the FA-bus Type 2 module
mounted in each unit.
The following pages show the relationship between a transmission cable discontinuity
and the status of the LEDs of the FA-bus Type 2 module. Bold lines in the figures
indicate active lines.
In the loop configuration, a
“subunit line switchover” message is logged by the system if
transmission is automatically switched from the primary loop to the secondary loop due
to a transmission cable discontinuity in the primary loop. In this case, the ALM LED is lit
but the ERR LED is not lit and operation continues.
Note
In the event of cable discontinuity in only one side of the twisted cable, ERR does not
light up