Siemens SIMATIC CP 541 Manual page 97

Table C-7 COM Parameters, continued
Parameter Values
UPDL 0 ... 10
PRI 0, 1 ... 30
Example of COM
Communications Processor CP 541
EWA 4NEB 812 6188-02
Update delay (receive delay time)
With the receive delay time, you specify the time after which a new message can be
sent from the CP 541 to the connected programmable controller. If you enter the
value 0, there will be no delay and a message received from SINEC L2 will be im-
mediately sent to the connected programmable controller.
The receive delay time depends on the processing speed of the user program in the
connected programmable controller.
The receive delay time must be 100 ms for S5-95F and S5-115F. With all other
PLCs, UPDL can assume all values.
Enter the receive delay time in multiples of 10 ms.
UPDL has the internal default 10 (= 100 ms), even with no specification in DB1.
Priority list
With a maximum of 60 entries, separated by blanks or commas, you use the priority
list to specify the priority of individual messages relayed from the CP 541 to the
connected programmable controller. You can also designate individual station num-
bers more than once.
On account of the lower transmission rate on the connecting cable between the CP
541 and the connected programmable controller, there may be more than one mes-
sage in the CP 541 for the connected PLC.
If the CP 541 receives a new message from a station, although the previous message
of this station has not yet been passed on to the connected programmable controller,
the old message is overwritten by the new one.
If you do not specify a priority list, the CP 541 internally enters all station numbers
(station number 1 to 30), even without a specification in DB1. The own station num-
ber will be deleted. If you use the DP connection, the CP 541 additionally enters 0. If
you only install a DP connection and set STA = PAS, the internal priority list will
only contain 0.
With the self-defined priority list, the CP 541 will only transmit messages of the spe-
cified stations to the connected programmable controller.
For sending via SINEC L2, the priority list is not significant.
The following example shows the contents of block COM. Node address 0 is
converted to station number 8.
The connected programmable controller is interrogated every 100 ms; you
used service access point 52 for the broadcast. The receive delay time for two
successive messages is preset to 100 ms.
Messages are received from stations 1, 2 and 6. Messages from station 1 are
passed on to the connected programmable controller with priority.
0: KS ='COM:
12: KS ='L1M 8 POL 10 PRI 1 6 1 2
24: KS ='BSAP 52 UPDL 10
Parameters of DB1
Meaning
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