Modbus Watchdog; Figure 47: State Diagram, Advanced_Watchdog Operation Mode - WAGO 750-8215 Manual

WAGO-I/O-SYSTEM 750
750-8215 PFC200; G2; 4ETH CAN USB
9.2.1

Modbus Watchdog

The Modbus watchdog monitors in the Modbus slave the ongoing Modbus
communication with the Modbus master. All valid Modbus requests of a Modbus
master from all the services supported by the Modbus slave are trigger events
(see chapter "Modbus Mapping"). Exceptions here are the Explicit Trigger mode
and the access to the register 0xFA02 (Watchdog Status), which can be
configured via the register 0xFA03 (Watchdog Config).
The "Watchdog Timeout" response is initiated if no trigger occurs within the
timeout set in the register 0xFA01 (Watchdog Timeout) with the watchdog
running. The closing of all Modbus TCP connections can be configured as a
response, see register 0xFA03 (Watchdog Config).
The Modbus watchdog supports two different operation modes
ADVANCED_WATCHDOG and SIMPLE_WATCHDOG. The operation mode can
be selected via Bit 7 in the register 0xFA03 (Watchdog Config).
The following diagrams show the possible states of the Modbus watchdog and
status transitions for the particular operation mode.

Figure 47: State Diagram, ADVANCED_WATCHDOG Operation Mode

Version 1.2.0, valid from FW Version 03.02.02(14)
Modbus – e!RUNTIME 229
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