Chapter 6. Errors and error recovery
6.2 Error
displays
The LED displays when the following errors occur are explained below.
(1) Normal operations (LED display status and module status)
Status of LED indication & Condition of Link Module
RUN
ERR
CPU LINK
EH-OLNK
TXD
RXD
The RUN LED lights. The TXD and RXD LEDs blink while link data
is being transmitted to/from other link modules.
The same display will apply when a [data link possible] error occurs.
(2) Hardware error (when watchdog timer errors and ROM/RAM errors occur)
Status of LED indication & Condition of Link Module
CPU LINK
EH-OLNK
RUN
ERR
TXD
RXD
The ERR LED lights.
Communications with other link modules will not be performed.
(3) Configuration error (duplicated station No.s, station No.s outside of the permissible range, etc.)
Status of LED indication & Condition of Link Module
CPU LINK
EH-OLNK
RUN
TXD
RXD
ERR
The ERR LED blinks every 0.5 second. (0.5s ON / 0.5s OFF)
Communications with other link modules will not be performed.
(4) Communication error (transmission errors, peripheral data receiving errors, etc.)
Status of LED indication & Condition of Link Module
CPU LINK
EH-OLNK
RUN
TXD
RXD
ERR
The ERR LED blinks every 1 second. (1s ON / 1s OFF)
Communications with other link modules temporarily suspended.
(Communications with other link modules will not be performed if the
same error occurs frequently.)
6.3 Clearing
errors
The link module error will be displayed in the ERR LED and the CPU module's special internal output
(WRF0E0 to WRF19F.) The methods of clearing each of these errors are explained below.
(1) Clearing the ERR LED display
Eradicate the cause of the error, and then press the error display clearance switch or the reset switch on the
front of the link module.
Note #1: The ERR LED will not be extinguished if the error display clearance switch is pressed without
eradicating the cause of the error. Also, the error display clearance switch is only for clearing the ERR
LED display, and it will not clear the CPU's special internal output area explained in item #2.
Note #2: The CPU module will detect a [Link Module Error] when the reset switch is pressed.
(2) Clearing the CPU module's special internal output
The information relating to errors contained in the special internal output is cleared by setting the CPU
module's special R7EC internal output to ON when errors occur. The link module's local station error
information (WRF0E0 and WRF140) is cleared in the same way.
Note #3: If the cause of the error is not resolved, the information remaining in the link module will not be
cleared even when R7EC is set at ON because it is overwritten into the CPU module. In this event,
resolve the cause of the error in the link module, press the reset button, and then set R7EC at ON.
6-2
