Subject: From: Date:

LM34 Temp conversion Lowell Ashley Thu, 5 Aug 2004 07:22:34 -0500

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----- Original Message ----- 
From: <ecs-digest-help@netbloc.com>
To: <ecs@netbloc.com>
Sent: Wednesday, August 04, 2004 9:59 AM
Subject: ecs Digest 4 Aug 2004 14:59:29 -0000 Issue 196
Mike,
 The LM34 can be used to generate 10mv/deg or even  .1mv/deg. I have done
this with op amps to set the gain(which is more accurite than useing
softearte to set the gain).
 My boiler temp reads from 100 deg F to 180 deg F. My inside temp reads 55
deg F to 95 deg F (anything outside this range is undesirable). The attic
temp is read from 80deg F to 160 deg F.
 I would be happy to fax/ e-mail/ phone support if more information is
needed including schematic of circuit.
The process is: 1) determine desired range ie: 55 deg F to 95 degF = 40 deg
delta
                        2) devide 5(full scale of Secu-16 analog input) by
40(desired range) = .125mv/deg F (the op amp is adjusted to produce 0 to 5
vdc for this reading)
                        3) ECS is the used to calculate conversion. ie:
; the analog reading at SECU-16 must de devided by 51 to obtain it's
; real value. Then the amp factor of the sensor ( in this case .125mv
; per deg.) is devided in to the analog input also. ( ie. 51x.125=
; 6.375 or 6.38 - Multiply by 100 and devide by 638 ) Last, the base
; is added to the resultant ( in this case 0 is 55 deg. at the sensor
; amp so 0 deg to 54 deg gives no reading output at the sensor amp
; and must be added back to give real vaue ).
; -------------------------------------------------------------------
Do         Number-E                Set        UP Temp
Do         Number-E                Multiply   100
Do         Number-E                Divide     638
Do         Number-E                Add        54
Do         Up Temp Real            Set        Number-E
 Hope this helps,
Lowell


From: Mike Barford [mailto:mbarford@mbatechi.com]
Sent: Tuesday, August 03, 2004 7:52 PM
To: ecs@netbloc.com
Subject: Re: [ecs] Analog readings from Ocelot

I believe that the Ocelot analog is an 8-bit value correlating to the
voltage of the input.
0 Volts = 0 and 5 Volts = 255. This means you have to use linear sensor to
be accurate.
This is the way that the Stargate works. In their software they have certain
calibration options.
I like to use LM334 temperature and an OP-Amp to make the sensors read at
10mv/degree  instead of the standard 20mv/degree F (This cause a minimum of
2 degree F resolution)
Many inexpensive sensors come in 0~5 VDC as an input option.
I saw your discussion about what system to use on this forum.
I don't like using programmable controllers when all I really want are the
inputs and outputs,
ECS is surely smarter than any process or programmable control on the market
today, so why pay for something you end up not utilizing to it fullest?
If you are interested, I could discuss what I use in more detail.
Best regards,



Mike Barford



PS: the analog reading are integers, but they can manipulated  with floating
point.

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