Siemens Simatic PCS 7 Commissioning Manual page 36

Engineering
4.3 Parameter assignment
Bus parameters Setting range (default
setting)
T1 -
Inter Sequence (480 000
Timer
corresponds to
approximately 15 s)
T2 T2 >= T3 + 3*T1 (host)
Set Addr (2880000
Sequence Timer
corresponds to
approximately 90 s)
T3 -
Set Addr Wait (1 440 000
Timer
corresponds to
approximately 45 s)
"Node Polling" area
Bus parameters Setting range (default
setting)
First Unpolled 20 < FUN < 232
Node
Number of NUN = 232 - FUN
Consecutive
Unpolled Node
"Other bus parameters" area
Select the checkbox to set the parameters:
● Checkbox "Automatic calculation"
● Checkbox "Manual entry"
36
Meaning and limiting values
The parameter T1 specifies the number of clock cycles that an interface module
(or an LAS) waits for a response from an FF device.
If the set number of clock cycles is exceeded, the service for this FF device will
terminate with an error message.
The parameter T2 specifies the number of clock cycles that is available to an
FF device for actions and data transfer. Any unperformed actions and data
transmissions are cancelled.
FF devices newly connected to the FF segment can only be detected if the value
T2 is sufficiently dimensioned.
Parameter T3 corresponds to a waiting time (number of clock cycles).
On expiration of this waiting time the interface module (or LAS) checks the FF
devices that are recognized as new on the FF.
Meaning and limiting values
FirstUnpolledNodeId (FUN)
(Default setting in SIMATIC STEP 7 / PCS 7: FUN = 36)
This parameter specifies the first device address that is not processed (not
polled) by the LAS.
NumConsecUnpolledNodeId (NUN)
(Default setting: NUN = 232 - 36 = 196)
Range of consecutive device addresses not in the polled range.
In SIMATIC STEP 7 / PCS 7 (Unpolled Bereich):
Default setting of 36 - 231
The bus parameters are automatically set on the basis of the current configuration.
You can change the following parameters for each specific system.
FOUNDATION Fieldbus
Commissioning Manual, 03/2013, A5E03880935-02