Temporal Characteristic Constraints between SP and PG of SAE J1939 in Passenger Car Information Integrated Control System

As a higher layer protocol based on CAN (Controller Area Network), SAE J1939 has specified SP (Suspect Parameter) and PG (Parameter Group) which respectively represent signal exchanged between ECUs (Electronic Control Units) and message containing a set of SPs. There is temporal characteristic constraint, such as period and deadline, between SP and PG in SAE J1939-based passenger car information integrated control system. According to the periods of SPs, it is easy to deduce that the period of PG is the minimal period of SPs composing this PG. Considering the possible offset between the production time of data of SP and the first production time of PG containing this data, the calculation formula of deadline of PG is deduced by applying the relationship between the production times of two periodic SPs. Vice versa, the given temporal characteristic of PG will also constrain the period and deadline of SPs composing this PG. According to two requirements, (1) deadline of PG equals to the minimal deadline of SPs composing this PG and (2) temporal characteristic of PG containing these SPs has been specified in advance, the temporal characteristic constraints of SPs are put forward.