Samson 3730-5 - Other Parameters; Stale Counter; Link Objects; LAS Functionality

17.3 Other parameters
17.3.1 Stale Counter
The Stale Counter serves to judge the “quality” of a process variable received over a config
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ured cyclic connection (publisher/subscriber connection).
These connections are used to transfer the process variable linked amongst the various func
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tion blocks. For this purpose, the upstream block (publisher) sends the process variable over
the bus at scheduled times. The downstream block(s) (subscriber) responds at the scheduled
times. The blocks that are to receive data monitor whether a valid value exists at the sched
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uled time. A value is valid if it exists with the status “Good” at the scheduled time.
The Stale Counter defines how many “Bad” (stale) values can be accepted in sequence be
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fore the Fault State of the block is activated.
This monitoring function is deactivated by setting the Stale Counter to zero.
17.3.2 Link Objects
Link Objects are used to link the inputs and outputs of the function blocks (configurable cyclic
connections).
A maximum of 22 Link Objects can be configured for each positioner.
17.3.3 LAS Functionality
The number of links and schedules that can be used is matched to the requirements of stan-
dard process control systems available on the market.
The positioner functioning as an LAS can support the following:
4
1 schedule
4
1 subschedule
4
25 sequences per subschedule
4
25 elements per sequence
In the delivered state, the positioner is configured as a basic device.
118 EB 8384-5 EN
Appendix