VIPA System 300V - System Properties of the CPU 31 Xnet

Chapter 6 Deployment CPU 31x with TCP/IP Manual VIPA System 300V
6-36 HB130E - CPU - Rev. 11/50
System properties of the CPU 31xNET
System properties of a CP are not restrictions or failure reactions. Certain
functions can not be provided or are not desired when the overall system is
taken into account.
• The boot time of the CP section of the CPU 31xNET is app. 18 seconds.
The integrated SYNCHRON block caters for this boot time (delay time
30s).
• Under the communication type TCP/IP the joker length (-1, FFFFh) for
the ORG format length definition is not permissible, i.e. that the user has
to specify a defined length of receiving data.
If you use a RCF1006 connection instead, you may set the joker length
at RECEIVE jobs (-1, FFFFh).
• RECEIVE jobs that are mapped to communication type UDP cannot
receive all data messages from a fast cyclic station. Messages that have
not been received are discarded.
• The protocol stack TCP/IP has a global buffer pool, where the receive
and transmit buffers are located. This is where system collisions can
occur if:
− data for a receive job is not collected. After a period of time a lack of
resources will occur and the other connections will terminate after the
defined time. A complete communication may started again when the
receive buffer of the one connection part is released again
(connection termination) res. the data has been requested with the
RECEIVE-HTBs.
− one or more cyclic stations place a load on a CP. When resource
bottlenecks are encountered, the CP can also initiate the termination
of connections.
− A station transmits two or more messages and the receiver did not
have a chance to accept them, then the reception of the unknown data
type would cause collisions in the receiver. However, the CP prevents
this. The PLC application requires are defined size for the reception of
data and the default or wildcard length is not permitted.
− VIPA recommends the use of acknowledgment messages on the
user level to ensure that data transfers are 100% safe.
Note
Specials under
TCP/IP