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hi there
Are there some people here who have experience using CAN (DeviceNet, CANopen, SDS, whatever...) as fieldbus with 1km bus length or more?
I am an electronics engineer and i would like to use CAN to interconnect embedded processing boards (custom designed), based on a
microcontroller with CAN build-in. The application has the following requirements:
- The main purpose is to boadcast relatively short 'strings' (16 to 32 bytes) in a building-automation application.
- Hard real-time performance is not required (<= 50ms is ok)
- Bus load (traffic) is low
- Maximum devices is 32.
- 10 or 20 kbit/s is fast enough
- inter-operability with other manufacures not required
- Total bus lengt can be more that 1km, but never more than 6km
(Don't bother pointing me to LON - it is not an option)
The thing that worries me is the bus lenght of 1km or more. The signal needs to be able to travel twice the distance of the line (+delays in
electronics) within the 'bit time' because of the CSMA-style protocol with arbitration. (using bridges to span the total 6km is acceptable,
but one segment should be able to be 1km). Now, i have found some sources on the web that talk about 1km being ok at 50kbit/s and even 2.5km
at 20kbit/s, 10km at 5kbit/s. But this is all very academic.
So my question is: does anyone have actual experience using CAN with 1km, or more, bus segments? Is it stable or did you experience many
problems?
Thanks.
Are there some people here who have experience using CAN (DeviceNet, CANopen, SDS, whatever...) as fieldbus with 1km bus length or more?
I am an electronics engineer and i would like to use CAN to interconnect embedded processing boards (custom designed), based on a
microcontroller with CAN build-in. The application has the following requirements:
- The main purpose is to boadcast relatively short 'strings' (16 to 32 bytes) in a building-automation application.
- Hard real-time performance is not required (<= 50ms is ok)
- Bus load (traffic) is low
- Maximum devices is 32.
- 10 or 20 kbit/s is fast enough
- inter-operability with other manufacures not required
- Total bus lengt can be more that 1km, but never more than 6km
(Don't bother pointing me to LON - it is not an option)
The thing that worries me is the bus lenght of 1km or more. The signal needs to be able to travel twice the distance of the line (+delays in
electronics) within the 'bit time' because of the CSMA-style protocol with arbitration. (using bridges to span the total 6km is acceptable,
but one segment should be able to be 1km). Now, i have found some sources on the web that talk about 1km being ok at 50kbit/s and even 2.5km
at 20kbit/s, 10km at 5kbit/s. But this is all very academic.
So my question is: does anyone have actual experience using CAN with 1km, or more, bus segments? Is it stable or did you experience many
problems?
Thanks.
