Hi,

I was in your situation a couple of years ago. I went with the dip switches=
 (or =

actually two BCD rotary switches - 00-99) and I am glad I did.

The switches are used to set the address of an RS485 node in a network =

connected to a PC. Normally there are between 3 and 50 nodes in a system. T=
he =

end user only has to connect the unit and set the switches according to a =

physical location. He doesn't need to keep track of the address with labels=
 or =

serial numbers since he can see it on the switches. This also means that it=
 is =

very easy to replace a node or even to switch places with another node.

The end user is a category who isn't (or at least wasn't at that time) very =

used to computers (not all of them but many) and making sure that they woul=
d =

program a node before inserting it in the system would not have worked and =

would have dramatically increased the "hands on" service calls because "it =

doesn't work" or "how do I do that?" (even if there are printed manuals).

Also, data from the node is connected to a physical location and is shown o=
n =

the screen at that location. If the node is programmed wrong, data for one =

location could show up on another location on the screen making the whole =

system more or less useless (it is used to alarm for abnormal values).

I guess it all comes down to who is going to use the equipment and how it i=
s =

going to be configured/programmed. If there are other settings that has to =
be =

set anyway, then there is not much use for physical switches I guess. =


Or, in other words - It depends....

/Ruben

> I have a client who I am working on a design with, where the PIC has a se=
rial
> port on it, and as such, is looking for data only thats addressed to it, =
in a
> broadcast mode.  Essentially the end user will plug his PC into this, and
> query it for logging data sending only with the header containing the add=
ress
> for this unit.
>    =

>   He wanted a set of dip switches to setup the addressing, and at first I=
 was
> onboard with him on this but now that its nearly working, I'm rethinking =
this
> (before I spin the board).
>    =

>   My issue is...its a cost adder, and somewhat of a hassle in build to set
> this up.  I can save him $10 in parts overall by dropping those.  What it
> means is, when the end user sets things up for the first time, he will ha=
ve to
> send a command setting the address.  As long as its documented well, then=
 I do
> not see that being an issue.
>    =

>   So, just looking for opinions....hardwire the address, or do a single o=
ne
> time setup?
> =

>        =

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124, 200 39 Malm=F6, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
ruben@pp.sbbs.se
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
-- =

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