CAN TPDO send rate

3 years 6 months ago #29532757 by kacox
CAN TPDO send rate was created by kacox
I am trying to get encoder values from my FLB2360 to my application at a 1 ms interval using the CAN bus. My initial design was to copy the encoder data into VAR 9/10 using a Micro Basic script with the controller configured to output TPDO 1 at a 1 ms send rate (TPDO 2-4 defaulted to 0 ms). Before implementing the script, I did some timing analysis of the TPDO 1 output rate. Instead of the expected 1 ms/frame inside my application, I am seeing ~4 ms/frame. If I choose a TPDO 1 send rate of 10 ms, I see around 12-13 ms/frame. Is this expected? I am not using a CAN bus sniffer, just O/S clock function calls to do the timing measurement. The micro-controller to capture the frames is a BeagleBone Black with a simple CANOpen test program to read the frames.

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3 years 6 months ago #29532758 by niko
Replied by niko on topic CAN TPDO send rate
Hello,

This is a known issue and is a matter of the CANOPEN stack limitation, which is 3rd party. Unfortunately the send rate cannot be any faster. 4ms is the faster it can get

If send rate 1ms is a necessity, check if you can use RawCAN and write a script in order to send CAN frame every 1 ms. We have not try it but seems doable.

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3 years 6 months ago #29532763 by kacox
Replied by kacox on topic CAN TPDO send rate
Is this also a limiting factor for RPDO messages going into the controller? If I send an RPDO message from my application at 1 ms will the controller see them at that rate?

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3 years 6 months ago - 3 years 6 months ago #29532764 by niko
Replied by niko on topic CAN TPDO send rate
Hi, we have not tested it, but there is possibility to freeze the stack, and maybe nothing else to be able to be sent.
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