On Fri, 15 Apr 2022, gene heskett wrote:
Date: Fri, 15 Apr 2022 14:38:03 -0400
From: gene heskett <[email protected]>
Reply-To: "Enhanced Machine Controller (EMC)"
<[email protected]>
To: "Enhanced Machine Controller (EMC)" <[email protected]>
Subject: [Emc-users] For Peter Wallace
Hi Peter;
It looks as if the inavailability of the high voltage op-amp I was going
to use will make me use just a part of the a/d range of a 7i76D first 4
inputs.
And, the relative lack of data for the MAP sensor I have two of, might be
a limitation too. The data is sparse, but what has me thinking is the
maximum current available at its output is shown as .1 milliamp, at full
scale which would roughly correspond to around 23 psig, or 38 psia, which
is what its actually measureing. And I want to regulate the pwm to a
bank of teeny conpressors that can do at least 10 psig, to around 4 or 5
psig. So rangewise its doable.
Since the max output currant is .1 milliamps, and I need to subtract
ambient pressure from whatever I measure when the conpressors are off.
This isn't super critical and its something I can do in the setup for the
program.
So my question then is how big a load is the a/d when doing the a/d for
for a 2 to 3 volt signal from the MAP sensor?
Thanks Peter.
The 7I76 field input load impedance for you (older) card woud be about 20K Ohms
If you dont need full scale, then a standard op amp buffer would do.
I do have a proto 7IA0 you might be able to use. It has 4x 0-3.3V
analog inputs (buffered so basically infinite impedance) free for cost of
shipping, but its a big card so not suitable if you are saving space
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users
