Siemens SINAMICS V20 - Usscyclic [FB1]

3 Principle of Operation
3.2 Blocks
SINAMICS V20 at S7-1200/1500 via USS
Entry ID: 109480894, V1.0, 09/2018
15
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Name
Data type
Meaning
OUT parameter
errorUss
Bool
Communication error
Saved ERROR error bit of the
USS_PORT or USS_Port_Scan
3
system instruction. In the
example, this error bit is reset
using the HMI or the watch table.
errorStatusUss
Word
Error code
Saved STATUS error code of the
USS_PORT or USS_Port_Scan
3
system instruction. In the
example, this error code is reset
to 0000
hex
using the HMI or the
watch table.
Function
In this application example, the block has only the following tasks:
 Calls and supplies the USS_PORT system instruction
 Saves the USS_PORT output parameter STATUS when ERROR = true
Call interval
On the one hand, the call interval of the cyclic interrupt OB in which the
UssCyclicInterrupt user FB and finally the UDD_PORT or USS_Port_Scan system
instruction are called
 should be as short as possible to minimize the communication time;
 on the other hand, it must be long enough to process each communication
request reliably without errors.
3.2.2 UssCyclic [FB1]
Call
All activities to be cyclically performed while processing USS communication
should be combined in this block.
Figure 3-6: UssCyclic user FB
The block name is intended to indicate that the FB is called by a cycle OB.
3
Communication errors are only signaled at the ERROR and STATUS outputs of the
*) USS_PORT instruction. Therefore, it is sufficient to read out the error code of this
*) system instruction.