ET-7000/PET-7000 AIO Series User Manual, version 1.0.1 beta3 Page: 151
Copyright © 2009 ICP DAS Co., Ltd. All Rights Reserved. E-mail: [email protected]
Appendix B. Modbus Application Notes
B.1. Dual Watchdog
Dual Watchdog consists of Module Watchdog and Host Watchdog.
reset
2. The Hos
tware
f
ation
rn all
Modbus
1. The Module Watchdog is a built-in hardware circuit that will reset the CPU module if a
failure occurs in either the hardware or the software. If the application does not
refresh the watchdog timer within 0.8 seconds, the watchdog circuit will initiate a
of the CPU.
t Watchdog is a sof
function that can be used to
monitor the operating status o
the host. Its purpose is to
prevent network communic
problems or a host failure. If the
Watchdog timeout interval
expires, the module will retu
outputs to a predefined Safe
value (Refer to the Safe Value
application note), which can
prevent the controlled target
from unexpected situation.
AO address 40557 of the
ET-7000/PET-7000 series
register is the address of the Host
Watchdog timer, and will be stored
into EEPROM. The WDT function
will be disabled if the value is set to
less than 5 seconds.
