Technical data

13 Clock Services
The CP 5430 TF/CP 5431 FMS clock function is implemented by a clock
chip and clock software that uses the clock chip (clock task).
There are two basic clock functions:
1. The clock keeps the time on the CP 5430 TF/CP 5431 FMS within the
absolute limits of accuracy described in the technical data. This clock
continues to run during a power down as long as the battery voltage is
present.
2. The clock can also be used to synchronize synchronization frames so
that all the CP 5430 TF/CP 5431 FMS modules connected to the
SINEC L2 network and involved in synchronization have a relative de-
viation of 20 ms from each other. The transmitter of the clock message
must be the CP 5430 TF/CP 5431 FMS.
The clock message has a fixed format for SINEC which corresponds to the
TF standard (refer to Fig. 13.1). The transmitter has SAP 55 reserved for
transmitting the time of day message. The user does not need to assign
parameters to this, since the clock software does this automatically.
When using the FMA services and clock function at the same time,
remember the following special feature of the CP:
☞
If the CP is the active time transmitter (clock master) on the
L2 bus
and an FMA service is triggered at the same time, this
may lead to the cyclic transmission of the time of day being
delayed.
C8976060/02 Clock Services
13 - 1 Volume 1