Mitsubishi MELSEC-A Series Reference Manual page 156

7. DATA LINK SETTINGS
(3) Setting the monitoring time
The monitoring time can be set between 10 to 2000ms in units of 10ms. (The usual
setting is 2000ms.)
Setting the minimum value to monitoring time is valid for the case to immediately turn
off the output of remote I/O stations where communication error occurred.
Use the following procedure to set the minimum value to monitoring time.
(a) Set "200" (2000ms) to monitoring time and write the setting to the master station.
(b) Perform data link in the actual system and monitor the link scan by link monitor
of GPP connected to the master station. (Refer to Section 10.1.1 for the link
monitor.)
(c) Turn off the power supply to one of the slave stations so that the system
operates in the loopback mode.
(d) Read the maximum link scan time value.
(e) Add 50ms to the maximum link scan time value read out and set it as monitoring
time. When using the A70BD-J71P21/R21 or A7BD-J71AP21/R21 as a master
station, add 250ms to the maximum link scan time value and set it as monitoring
time.
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