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SyNCHRONIzATION ON VARAN fIeLDbUS
5 Synchronization on VARAN fieldbus
In order to ensure the data consistency when accessing to the dual port memory, the
internal calculation cycle must be synchronized to the external VARAN cycle.
For this, the external cycle time is defined by the parameter fb25. A PLL shifts the internal
calculation grid accordingly. If the synchronization is completed successfully, the syn-
chronous operation is shown over the VARAN status LED. See
Id-Text
fb25
Meaning
Type
Data length
Access
Coding
Note
Id-Text
fb26
Meaning
Type
Data length
Access
Coding
Note
20
Name
cycle time
Default of the external fieldbus cycle time
Variable
16 bit
read / write
0...16000 μs
Standard value: 0 μs
Value is not saved and always writing after switching on the unit.
Only integer multiples of 1000 μs are accepted.
Name
set sync level
Maximum permissible deviation of internal to external cycle time
for which the communication is rated to be synchronous.
Variable
16 bit
read / write
0...100 μs [multiplier: 1, divisor: 10, offset: 0]
Standard value: 2 μs
-
„Light-emitting Diodes".
Parameter index
0x2199
Parameter index
0x219A
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