Technical data

Selecting the GAP update factor:
The GAP update factor decides how many token rotations take place before
all the active stations check their GAP area.
If you require a low bus load, select a high GAP update factor. Stations that
have dropped out of the ring and wish to re-enter it are registered later in
this case.
If, on the other hand, you want such stations to be included in the ring as
soon as possible, then select the GAP update factor as small as possible.
This increases the bus load (more frames due to additional GAP frames).
The more stations connected to the bus, the lower the relative load caused
by GAP frames. If the station addresses and HSA are selected optimally, a
GAP update factor on 1 can be selected.
Example of calculating the target rotation time (TTR) with the following
bus configuration:
Three stations are connected to the SINEC L2 bus:
Addresses: 1, 2 and 3
HSA: 3
GAP update factor: 1
Data rate (in Kbps): 187.5
Volume of frames:
station 1: 1 SDN frame with 10 bytes of transmitted data
station 2: 1 SDN frame with 10 bytes of transmitted data
station 3: 1 SDN frame with 10 bytes of transmitted data
1 SRD frame with 20 bytes of transmitted data and 10
bytes of received data.
Appendix B8976060/02
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