Mitsubishi Electric MELSEC iQ-R Series User Manual page 86

Cyclic transmission assurance by watchdog counter
The watchdog counter is a function used to assure normal cyclic transmission between stations on CC-Link IE TSN.
Using the watchdog counter, the master station and a device station mutually monitor the data to be updated every
communication cycle; the master station monitors data received from a device station and a device station monitors data
received from the master station.
If "Synchronous watch dog counter error (error code: 1D20H)" has occurred, data of that station will not be received even after
the watchdog counter returns to normal. To restart, turn on the power supply of the Motion module again, reset the CPU
module, or disconnect the device station and return it.
• Whether the device stations performing data link with the master station is using the watchdog counter can
be checked from 'Watchdog counter operating status information for each station' (SW01D0 to SW01D7).
• "Synchronous watch dog counter error (error code: 1D20H)" will be detected for device stations without axis
setting with the motion control setting function. For device stations with axis setting, "WDT error" (error
code: 1C41H) will be detected instead.
• If "WDT error (error code: 1C41H)" has occurred, operation can be resumed by performing error reset.
Before using this function, check the add-on baseSystem version of the Motion module. For details, refer to
"Restrictions by the version" in the following manual.
MELSEC iQ-R Motion Module User's Manual (Application)
■ Operation
When the master station is powered off and on (when the CPU module is reset) or a device station is disconnected and
returned, the master station stores insufficient time for the transient transmission time in 'Transient transmission addition time
(calculation value)' (SW007A).
If a value has been stored in 'Transient transmission addition time (calculation value)'' (SW007A), add the value to the setting
values for "Communication Period Interval Setting" and "Transient Transmission Time' of "Communication Period Setting"
under "Basic Settings" of the module parameter of the master station.
■ Setting method
The settings of the master station are not required to use the watchdog counter. However, the settings may be required
depending on a device station used. ( Manual for the device station used)
Precautions
When the Motion module with the add-on baseSystem version "1.15" or earlier is used or a device station does not use the
watchdog counter, 0 is stored in 'Transient transmission addition time (calculation value)' (SW007A).
Network synchronous communication with a local station
A local station can link network synchronous communication and the inter-module synchronization function, so the local
station can operate in synchronization with the inter-module synchronization cycle of the master station. For details, refer to
the following.
MELSEC iQ-R Inter-Module Synchronization Function Reference Manual
Program example
For program example using the inter-module synchronization function, refer to "Inter-Module Synchronization Function" in the
following manual.
MELSEC iQ-R Motion Module User's Manual (Application)
1 FUNCTIONS
84
1.6 CC-Link IE TSN Network Synchronous Communication Function