SAE J2728-1:2020 pdf free

SAE J2728-1:2020 pdf free.Heavy Vehicle Event Data Recorder (HVEDR) – Data and Triggers
1. The recommended default 11.3 km/h/s (7.0 mph/s) acceleration trigger is specified for typical on-highway heavy truck applications. Recognizing that other vehicle configurations, applications, or vocations may require adjustment to the event trigger vehicle speed rate of change, the rate may be programmable within the range per the above specifications.The 0.5 second persistence requirement remains in effect over the allowable range of the programmable event trigger and is intended to reduce“false” events from noise in the VSS signal. The HVEDR should include appropriate filtering to avoid triggering extraneous events due to ABS cycling.
2. The VSS is not always an accurate representation of the velocity of the chassis relative to the ground.
3. The suggested threshold persistence of 15 seconds for the last stop trigger is to reduce the number of write cycles to non-volatile memory for stops that are very short duration. It is not intended to prohibit the recording of shorter duration stops.
The data elements listed in this recommended practice are only relevant if the vehicle is equipped with the associated sensor and/or vehicle system and their status is available to the HVEDR. While the HVEDR manufacturer can determine which data elements are applicable their system, manufacturers are referred to Table 2 for a list of recommended data elements as a minimum. Users of this recommended practice may include data elements beyond those listed in Table 2. It is recommended to use SAE J1939-71 as a reference for formatting the data elements where applicable.
NOTE: The comment field in Table 2 lists signals from SAE J1939 that represent the intent, possible source, and format of recommended data elements. Other proprietary or internal signals may be substituted or required to meet the intent of the recommended practice. Control systems are listed below with suggested signals, where available, to represent whether the system is operational and whether it is actively controling or alerting.SAE J2728-1 pdf free download.