Specifications

The CP143plus firmware CP143 H1 / TCP/IP manual
4-12 Rev. 00/07
4.2.3 Further information on the CP143plus
4.2.3.1 System properties
The system properties of a CP must not be regarded as limitations or as design faults. Instead,
certain functions may not be accessible or they have been removed for the security of the overall
system.
• The run-up time of the CP143plus is app. 10 seconds. For this reason the requirements of
balanced synchronization characteristics (an HTB synchronization module waits between 8 and
10 seconds, depending on the type of CPU) can not be met. Thus the start-up OBs 20-22 must
perform the following actions:
• poll the PAFE of the HTB in synchronous mode until this becomes 0. After 10 seconds
the tile will be set to active by the CP.
• If the synchronous HTB still detects a PAFE after 15 seconds then the PLC, the
configuration of the PLC or the CP is incorrect. In this case the respective configuration
must be checked.
• Depending on the sequence in which the synchronous HTBs were initiated, the CP may detect a
synchronous request and re-boot when more than one tile of a CP must be synchronized. Under
these conditions the CP would never be synchronized. Cure: switch the CP to STOP by means of
the respective switch, then synchronize all the required tiles. Change the switch back to RUN. At
this point the CP has been synchronized. This reaction of the system can only occur during
commissioning, and then only, if the number of tiles of the CP is increased and the new
synchronous HTB is not accessed as the last one in the sequence.
• Tasks having a priority of 0/1 can only send and/or receive the amount of data as defined by the
synchronous HTB. Tasks of this type are not blocked. This results in a maximum data transfer
rate of 512 bytes per task and a block size of 255 (see also block size).
• RECEIVE tasks, that are mirrored as broadcast communication, can not receive all data messages
from a fast cyclic transmitter. Messages that have not been received are discarded to protect the
system.