Simple System for newbee

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Hi there

This is not a request for me, as I normally use Cygnal '51 derivatives for
development. But one of my colleagues has a boiler and an airconditioning
and he needs to control it.

He needs to monitor perhaps two analog values and respond setting two relays
to switch the respective systems on/off.

A further demand is that he needs a display to set different parameters for
the system and it must be easy to get the system up and running.

However he does not have overly much time and not much experience either

I suggested two ways:

1. Use a 8051 development kit with a 2x16 LCD display and use c-compiler to
program the thingie. Construct driver circuits to control the relays. This
is heavy on the coding part, but cheap. But in this case I don't know what
systems out there offer micro with display included?

2. Use an old protable PC that can run in harddisk power-down mode all the
time and use aquisition hardware (www.pico.com) to read the analogue values
and other board to control the relays. This can be up and running in no time
and moreover he can use a windows GUI C-compiler to create a windows
application that will quickly get him to the end.

What are your recommendations on these?

Thanks

Klaus



Re: Simple System for newbee
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Okay... So here, we have the following confluence of circumstances:

1. Time pressure.
2. Extremely simple tasks.
3. Inexperienced user looking for a practically turnkey solution.
4. Expensive, perhaps even dangerous outcome from improperly designed
system.

I would buy an off-the-shelf thermostat designed for use with reverse cycle
AC/heating units. This will not only turn on the AC at the upper temperature
point, and turn on the heat at the lower temperature point, but it has an
implicit mutualexclude preventing both systems from running simultaneously.
It will be plug-n-play.





Re: Simple System for newbee
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My coworker controls boilers with the help of a board, based on Atmel
ATmega16. It does almost exactly, what you have specified: controls
4-20mA inputs and switches some triacs, controlling servomotors.
ATmega16 satisfies him in full.

Re: Simple System for newbee
snipped-for-privacy@hotmail.com (Alexander Baranov) wrote in message
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What about the display. Does he simply use a serial controlled
display? That seems very simple, you just do a PutChar and you have
transmitted one command. Anyone used these serial buggers?

Thanks

Klaus

Re: Simple System for newbee
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I don't know exactly how your colleague balances the need for
easy-development with price... and the following will certainly be
overkill when you can pull together a ~$30 solution with the 8051
approach.

But with that disclaimer out of the way, maybe he could use something
like our TD40 product, with the 11 ch. 12-bit ADC and TD-Pack
(LCD/keypad) option.  Easily C/C++ programmable (x86 real mode w/ 512
KB Sram/Flash) to do all of the above.  Total price: about $290 in
single quantities.

Like I said, this may be overkill: 21 solenoid driver outputs (350 mA
@ 50V), 14 HV inputs, 45+ TTL I/Os, 16x2 LCD, 8x2 keypad.  Power it
with 9-12VDC (or up to 35VDC if you get the switching regulator
option).

http://www.tern.com/td40.htm

We have a lot of other less expensive options as well, but he'd have
to trade-off some of the specified features.  I'd be more than happy
to discuss the application in detail over email if needed.

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