Communications configuring
3-186
System- and communication configuring D7-SYS - SIMADYN D
Edition 12.2003
The time taken for the data to be transferred via the P bus is not relevant
for this estimation, as this data transfer time is generally less than 1ms
and generally, the function blocks TAB and TAB_D are configured in
sampling times which are greater than 32ms.
If a table is distributed over several data blocks, the time required
increases. The reason for this is that in addition to the time taken to
transfer the tabular values, which can be determined using the formula
above, the user has to manually make the changes described above.
3.18.3.2
Configuring for S7 control and SIMATIC FM 458 application
module
The following function blocks must be configured for the coupling
between an S7 control and an SIMATIC FM 458 application module via P
bus:
•
SIMATIC FM 458 application module:
−
TAB (for REAL data type) and/or
−
TAB_D (data type DINT)
−
@CPB (P-bus coupling, central block)
•
S7 control:
−
WR_TAB
Each table may only contain values associated with one particular data
type. If several tables with different data types are to be managed, then
an TAB or TAB_D must be configured for each table.
WR_TAB is used to transfer the tabular values from SIMATIC DB to
function blocks TAB and TAB_D. The tabular values are transferred using
a data telegram. When the last data telegram has been transferred, the
TAB or TAB_D is automatically signaled that all of the tabular values
have been transferred and that the table should be activated. WR_TAB
receives a checkback signal as to whether activation was successful or
not. After the table was successfully activated, its address is output at the
TAB output of the TAB or TAB_D.
TAB and TAB_D should be configured as follows:
They should be configured in a sampling time greater than or equal to
32ms. The following connection settings are required:
CTS
=
[name of the configured communications interface]
AUT
=
1 (automatic mode activated)
US
=
[channel name.address stage1] (address data for receive)
MOD
=
[data transfer mode] (H=Handshake; R=Refresh; S=Select;
M=Multiple)
TFT
=
[monitoring time in milliseconds] (maximum telegram failure time
TAB and TAB_D
