FPΣ
Communication Function 3 PLC Link Function
10 - 26
10.5.3 Error Detection Time for Transmission Assurance Relays
If the power supply for the PLC of any given station fails or is turned off, it takes (as a
defaultvalue)6.4 secondsforthetransmissionassurancerelayofthat PLCtobe turned
off at the other stations. This time period can be shortened using the SYS1 instruction.
Example of SYS1 instruction setting
SYS1 MPCLK1T1, 100
Function description: This changes the time that the PLC link transmission assurance
relay is off (default value = 6400 ms).
The above example shows the time being set to 100 ms.
Key words: Specification of No. 1 key word: PCLK1T1
Allowable setting range for No. 2 key word: 100 to 6400 (100 ms to 6400 ms)
Notes
Precautions concerning settings
The above instruction should be set up at the beginning of the
program, so that it is executed at the rise of R9014, and the
same value should be set for all of the PLCs in the link.
Executing the above instruction does not change any of the
system registers.
The SYS1 instruction should be set to a value at least twice
that of the maximum transmission cycle time when all of the
PLCs are connected to the link.
If a short value has been set, there is a possibility of the
transmission assurance relay malfunctioning. However, the
shortest time that can be set is 100 ms.
The setting should not be changed as long as a longer
transmission assurance relay detection time does not cause
any particular problems.
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