Bus Master Functions

Bus Master Functions





The SIM has two tasks to perform as Bus Master for the byte flight.
^ Generation of the synchronization pulses (Sync. Pulse)
^ Setting the satellites in alarm mode (Alarm Pulse)
In the ASK, the SIM is configured as byte flight master (bus master). In principle, any satellite can be configured by software as bus master. However, there may only be one bus master in the system.
All other satellites (bus slaves) use the sync pulse for internal synchronization. Each slave can transmit telegrams between the sync. pulses on the byte flight.
The SIM provides the synchronization pulses at intervals of 250-s. The alarm mode is transmitted across the width of the sync. pulse. The duration of a sync. pulse in alarm status is approximately gas. Normally, the synchronization pulse lasts approximately ads. The duration of a complete telegram can vary between 4.6 to 1 gas.
On the basis of all the available information provided by the sensors, the bus master (SIM) must decide whether the satellites are to be set in the alarm mode.
When the alarm mode is set by the SIM, all the trigger circuits (B+) of the ASK are placed on trigger standby.