CAN REQUEST | AEM
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abdo28
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CAN REQUEST

HI what is the function of the can request on dash desigen softwear

AEM_HB
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CAN request is used for

CAN request is used for setups that do not simply output data, such as an obd2 setup or with the mefi4b. On these applications the receiving device (the cd-7) needs to request a message in order for the ecu to output data.

abdo28
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ok is there any plan on the

ok is there any plan on the future for the cd7 to transmit massages

AEM_JR
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Tbh, I really had not seen

Tbh, I really had not seen much of a need for it since the dash itself would not usually not be the original source of information. Since most (essentially all) of the data it has was received via the CAN bus then that data is already on the CAN bus so it doesn't need to be placed back on there.

Basically, the role of the dash as it has been designed is as a Display/Logging destination for the data rather than the source of any data. The current CAN transmit functions are designed to prompt some devices to send out their data or to acknowledge successful receipt of data, allowing the transmitting device to move on to additional data for transmission.

What kind of data do you want to be able to transmit?

abdo28
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it would be for example

it would be for example having aem infinty on modren cars by using the dash transmit you can send to other ecu ABS/EPS so they can function

since the aem infinty dont have can bus transmit
 

AEM_JR
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Ahh, OK I understand. You are

Ahh, OK I understand. You are looking for some CAN bridge type functionality. Taking in data and then forwarding it to other devices either in a different format or on a different bus.

Right now the CAN functions in the CD-5 and CD-7 have been tailored to it's assumed use as a Display/Logging data destination only.

highlander
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is this like a PID request?  

is this like a PID request?

 

AEM_NS
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Not specifically, no. It's

Not specifically, no. It's for requesting CAN outputs go live and start streaming data. Not for specific PID channel request. Not currently at least.

highlander
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The only way to do a mode 22

The only way to do a mode 22 PID request is to import a dbc file (sort of what you do with the probing of PIDs?) I want to add my own.... DMA PIDs would be awesome as there is some useful info like Torque Source/Spark Source/Throttle Source that can aid in visual inspection of something that might have happened...

 

AEM_NS
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highlander wrote: The only

highlander wrote:
The only way to do a mode 22 PID request is to import a dbc file (sort of what you do with the probing of PIDs?)

That's not at all how it works.  A DBC file defines a basic CAN protocol.  Mode 22 Data by Identifier PIDs is part of UDS which is defined in ISO 14229.  Diag over CAN is defined by ISO 15765.  The functionality of 14229 operates within 15765 and neither of which utilize DBC functionality.  There is a very specific way to communicate with an ECU in order to access and request DiD PIDs and that method has not been implemented in the CD dash nor is it something a simple DBC import can accomplish.  

highlander
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AEM_NS wrote:

AEM_NS wrote:

 

highlander wrote:

The only way to do a mode 22 PID request is to import a dbc file (sort of what you do with the probing of PIDs?)

 

That's not at all how it works.  A DBC file defines a basic CAN protocol.  Mode 22 Data by Identifier PIDs is part of UDS which is defined in ISO 14229.  Diag over CAN is defined by ISO 15765.  The functionality of 14229 operates within 15765 and neither of which utilize DBC functionality.  There is a very specific way to communicate with an ECU in order to access and request DiD PIDs and that method has not been implemented in the CD dash nor is it something a simple DBC import can accomplish.  

 

Thank you... if you could post an example of how this PID request works we can extrapolate. Thanks for the response