Driver Wdt Function - Mitsubishi Electric SW0DNC-MNETH-B User Manual

4 FUNCTION

4.3 Driver WDT function

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Driver WDT function monitors the operation of the software (operating system, driver)
inside the hardware by the timer function on MELSECNET/H board.
When the driver cannot reset the timer of the board within the specified driver WDT
monitoring time, MELSECNET/ board detects driver WDT error.
Driver WDT function detects driver operation delay due to the access error from the
driver to MELSECNET/H board or system high load.
(1) Driver WDT settings
For the setting method, refer to section 9.2.11.
REMARK
The driver WDT function is set to invalid as a default.
(2) When the driver WDT error has occurred
The following shows the operation when driver WDT error has occurred.
1) MELSECNET/H board and the driver stop communication and are
disconnected from the network in order to avoid an erroneous output.
A CPU stop error occurs when checking the MELSECNET/H board from
other station on which the driver WDT error has occurred.
2) RUN LED flicks and SD LED turns ON on the MELSECNET/H board.
3) "-28158 (9202H) Driver WDT error" occurs when accessing MELSECNET/H
board from the application program in which the MELSECNET/H utility and
MELSEC data link library function are used.
POINT
(1) When the multiple applications in which MELSEC data link library is used are
executed, driver WDT error is returned to all the programs. However, only the
MELSECNET/H board in which the driver WDT error has occurred is
recognized as an error station on the network.
When using driver WDT function, set the monitoring timer considering the
margin of the personal computer load.
(2) For the troubleshooting, refer to section 14.7.2.
MELSEC
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