remote frame in can bus in msg transmission

[jaga123]

what is the role of remote frame in can bus?

 

[ahamshubham]

CAN bus is used for data transfer between several electronic devices in a vehicle. Generally, data is sent by one device(transmitter) in the form of a data frame which is received by another device(receiver) for which the data is meant.
Also, the receiver can itself request for data from the transmitter. For this, the receiver sends a frame with no data, also known as remote frame. This remote frame has the same structure as the data frame except for the fact that there is no data present and the RTR bit is 1.

 

[jaga123]

thank you @ ahamsubham
but how receiver sent a remote frame to transmitter ?
means is it programmed by programmer or receiver do it itself? and if it do itself then how and when?

 

[ahamshubham]

Generally, every receiver and transmitter has an ECU (Electronic Control Unit). The electronic control unit has a microcontroller that performs all the basic data transfer operations based on the requirements. This microcontroller works based on some program fed into it and whenever there is need for some data the receiver will automatically send a remote frame requesting for the particular data.