Re: Serial Bus Choices

On 15 Nov 2006 10:22:01 -0800, "Joel" <joeldturner@xxxxxxxxx> wrote:

My company is designing the electronics for some UAV payloads and we
are trying to decide on an inter-module serial comm scheme.
Internally, we had chosen 485, but our customer asked why 485 and not
ethernet, firewire, 1553, CAN, or USB. I am working on an answer for
them and would like some input from this group.

We have some constraints on size, weight and shape because we will need
to fit into leftover space inside unspecified packages. This makes me
tend away from COTS plug-in-board solutions, which would make ethernet,
USB, or 1553 simple to implement.

Our controllers for these modules will likely be from the AVR family -
this is not set in stone but we already have experience with them and
the tools. We don't expect to have huge amounts of data on this bus
(it's mostly for command and status to a few sensors and motor
controllers) and we don't currently know how many nodes we will need.
The reason for having separate modules at all is to make it easier to
adjust for feature creep and add new functionality without respinning
every board when this happens.

I know there are some holes in this info and I will answer any
questions that I can.

Thanks,

Nice replies from all. But when you go to your customer and say, RS485
(or alternate solution) is the best value for money when it comes to
cost v reliablility i think your customer will be happy. Weigh up the
cost, then make a decision.

Tell them CAN will cost more, but is more robust or ethernet requires
more hardware (and subsequently $$) but is more scaleable etc. Do
yourself a favour and write down approximate costs of each solution
and next to that write down pro's v con's. Take several options to
your customer and let them choose which way they want to go based on
your educated opinion.

Someone is paying you, give them what they want and you will get more
work.
.

Relevant Pages

  • Re: Serial Bus Choices
    ... Internally, we had chosen 485, but our customer asked why 485 and not ... ethernet, firewire, 1553, CAN, or USB. ... The reason for having separate modules at all is to make it easier to ... Joel Turner ...
    (sci.electronics.design)
  • Re: Serial Bus Choices
    ... ethernet, firewire, 1553, CAN, or USB. ... But when you go to your customer and say, ... cost v reliablility i think your customer will be happy. ...
    (sci.electronics.design)
  • Re: Serial Bus Choices
    ... Internally, we had chosen 485, but our customer asked why 485 and not ... ethernet, firewire, 1553, CAN, or USB. ... Our controllers for these modules will likely be from the AVR family - ... Keep in mind that all the others (be it CAN, ethernet, firewire, USB, ...
    (sci.electronics.design)
  • Re: Serial Bus Choices
    ... Internally, we had chosen 485, but our customer asked why 485 and not ... ethernet, firewire, 1553, CAN, or USB. ... Our controllers for these modules will likely be from the AVR family - ... Keep in mind that all the others (be it CAN, ethernet, firewire, USB, ...
    (sci.electronics.design)
  • Re: Serial Bus Choices
    ... Internally, we had chosen 485, but our customer asked why 485 and not ... ethernet, firewire, 1553, CAN, or USB. ... Our controllers for these modules will likely be from the AVR family - ... Keep in mind that all the others (be it CAN, ethernet, firewire, USB, ...
    (sci.electronics.design)
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