Block library TeleControl ST7
5.7 Master copies
TIM 1531 IRC
Operating Instructions, 02/2018, C79000-G8976-C468-02
227
If the destination object number is not contained in the received data frame, FC Distribute,
which is responsible for distributing the received frames, references an object reference list.
Using the source address (source subscriber no. + source object no.) contained in every
data frame, FC Distribute searches through the list for an entry that specifies the missing
destination object number for the given source address; in other words, it searches for the
number of the local instance DB.
This object reference list is created by FC ListGenerator. The FC has no parameters. It is
linked into the cyclic user program (OB1) following the FC BasicTask.
When creating the list, FC ListGenerator uses the addresses set in the parameters for the
receiving typicals. Specification of "PartnerNo" and "PartnerObjectNo" is mandatory for these
typicals. These parameters are identical to the source address in the corresponding receive
frame. Since the typical also knows the number of its instance DB, it therefore knows all the
addresses required for an entry in the reference list.
During startup, FC ListGenerator arranges that all receiving typicals enter the addresses
from their parameter assignment with the number of the instance DB in the reference list.
The object reference list therefore does not require special parameter settings, it is simply
created from the existing parameters of the receive typicals and is therefore always
consistent.
How it works
FC ListGenerator creates the lists after startup in three consecutive OB1 cycles:
●
In the first cycle, it determines how many entries will be required in the first and, if
applicable, in the second object reference list. The typicals involved only increment a
counter during this run.
●
In the second cycle, FC ListGenerator generates the data block for the first and, if
applicable, the second object reference list with the required length and enters 0 in all the
data words. During the same cycle, all typicals involved enter their addresses and the
number of the corresponding instance DB in the list.
●
In the third and final cycle, FC ListGenerator sorts all the entries in ascending order.
Sorting speeds up the search in the list during actual operation.
When generating the data block, FC ListGenerator does the following:
If no list has yet been created, a free DB number is searched for. Starting with the number of
DB BasicData, the number of the next lowest free DB is taken.
If a list already exists, FC ListGenerator checks to see whether the existing DB is long
enough for the currently required number of references. If the length is adequate, 0 is
entered as the content and the addresses are written again and sorted.
