Siemens sinamics dcp Operating Instructions Manual page 210

Operation
8.6 Communication via PROFINET IO
Comparison between RT and IRT
Table 8- 28 Comparison between RT and IRT
RT class
Transfer mode
Isochronous application in
the IO controller
Determinism
Reload the network configu-
ration after a change
Maximum switching depth
(number of switches in one
line)
For possible send cycles, see subitem "Send cycles and update cycles for RT classes" in table "Adjustable send cycles
and update cycles"
Set the RT class
The RT class is set by means of the IO controller interface properties. If RT class IRT "high
performance" is set, it is not possible to operate any IRT "high flexibility" devices on the IO
controller and vice versa. IO devices with RT can always be operated, regardless of the IRT
class setting.
You can set the RT class in the HW Config for the associated PROFINET device.
1. In HW Config, double-click item PROFINET interface in the module.
The "Properties" dialog box opens.
2. Select the RT class under RT class on the "Synchronization" tab.
3. Once you have selected "IRT", you can also choose between option "high flexibility" and
"high performance".
Note
The "high performance" option must not be selected for SINAMICS DCP (an error
message is issued).
4. Confirm with "OK".
210
RT
Switching based on the MAC
address; prioritization of the
RT telegrams possible using
EtherNet-Prio (VLAN tag)
No
Variance of the transmission
duration by started TCP/IP
telegrams
Not relevant
10 at 1 ms
IRT "high flexibility"
Switching using the MAC
address;
bandwidth reservation by
reserving an IRT "high flexi-
bility" interval in which only
IRT "high flexibility" frames
are transferred but, for ex-
ample, no TCP/IP frames.
No
Guaranteed transmission of
the IRT "high flexibility" tele-
grams in the current cycle by
the reserved bandwidth.
Only when the size of the
IRT "high flexibility" interval
needs to be modified (reser-
vation of position is possi-
ble).
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Operating Instructions, 05/2016, A5E34382853K
IRT "high performance"
Path-based switching ac-
cording to a topology-based
plan; no transmission of
TCP/IP frames and IRT "high
flexibility" frames in the IRT
"high performance" interval.
Yes
Exactly planned transfer;
times for transmission and
receiving are guaranteed for
any topologies.
Always when the topology or
the communications relation-
ships change
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SINAMICS DCP