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(b) When the operation is switched between the master operation and submaster
operation
When the operation is switched between the master operation and submaster operation, a temporary data link
error is detected (SB0049 and SB00B0 turn on).
While the operation is being switched, do not use cyclic data and the following signals.
The time until the operation is switched varies depending on how the operation is switched as described below:
• When the operation is switched because the master operating station is down: up to three seconds
• When the operation is forced to be switched using Forced master switch command (SB0019): up to three seconds
• When the master station where "Return as Master Station" has been selected in the "Operation Setting for
Returning" field on the "Supplementary Setting" window returns: up to 20 seconds
(2) Programming for transient transmission
(a) Use of the REMFR and REMTO instructions
The REMFR and REMTO instructions can be executed only in a master operating station. Create a program
where these instructions can be executed only in the master operating station using Own station master/
submaster function operation status (SB004E) (a master operating station when SB004E is off).
Check that Data link status (own station) is normal (SB0049 is off).
(b) Use of the WRITE, SWRITE, RIWT, and REQ instructions
Data can be written from both of a master operating station and submaster operating station; therefore, create
a program where data are not written in the same area at the same time. Especially, pay attention when the
program of a master station is used for a submaster station. Use Own station master/submaster function
operation status (SB004E) to check whether the own station is the master operating station or submaster
operating station and do not execute the WRITE, SWRITE, RIWT, and REQ instructions at the same time.
Check that Data link status (own station) is normal (SB0049 is off).
(c) Dedicated instructions when the control is switched between the master operating
station and the submaster operating station or when the master station returns
Dedicated instructions may end abnormally (timeout error). Create a program where transient transmission is
performed again even if dedicated instructions end abnormally (timeout error).
Device Description Device Description
SB0049 Data link status (own station) SW005A Maximum baton pass station
SB0070 Master station information SW005B Maximum cyclic transmission station
SB0071 Submaster station information SW0064 Connection status (own station)
SB00A0 Baton pass status (each station) SW006D Master operating station number
SB00A1 Baton pass status (master station) SW006E Submaster operating station number
SB00AF Baton pass status (station No.0)
SW00A0 to
SW00A7
Baton pass status (each station)
SB00B0 Data link status (each station)
SW00B0 to
SW00B7
Data link status (each station)
SB00B1 Data link status (master station) X1 Own station data link status
SB00BF Data link status (station No.0) X3 Other stations data link status
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