A simple way to convert 0-20ma into 0-10volt

[me]

Back up and debate PIC versus AVR, and end up with a 68HC11.

I would think that the daunting task of controlling the whole works would
need the processing power of at least a blade server if not a serious
super computer.

 

[Rich Grise]

Back up and debate PIC versus AVR, and end up with a 68HC11.

The HC11 is a beautiful processor - it's just too bad they're so damn
expensive!

Thanks,
Rich

 

[joseph2k]

The HC11 is a beautiful processor - it's just too bad they're so damn
expensive!

Thanks,
Rich

Could that be because they are really ancient and EOL'd?

 

[Tony]

Linnix,

I believe that John was merely pointing out in a nice, polite way that
your posts are flawed with very basic misconceptions - not just a
matter of small adjustments or component values. You should re-read
John's posts in that light, and/or consult a tutorial on opamp circuit
design. For this application, an inverting topology is wrong, and the
rest just makes it wronger. If you really want to use an opamp (eg if
a low-Z output is needed), and in the absence of any other
information, a more logical way to do it is as a simple buffer, eg

+----------+
| \ |
| |\ |
+---|-\ |
| +---+--OUT
IN--+---|+/
500 |/
| /
GND

Tony

No, it will max out at Vcc.


Most of the current will flow to ground via the input R, not the
feedback R.


OK, we need the split the input current to avoid saturating the op-amp
too much. The values are just approxmation (in ratios), you have to
figure-out the exact values.

+------ 10K -----+
| |
| |\ |
| | \ |
IN----+------|- \----+---- OUT
| 1K | /
100 +------|+ /
| 1K | /
| | /
GND


But this is not open-loop.

Tony (remove the "_" to reply by email)

 

[vasile]

Hallo,
I should acquire an analog signal in current and convert it in voltage.

The signal is in 0-20ma current range.

I thoguht to use the following circuit:

Voltage source 5volt
|
R1
input 0-20ma------|------------ output about 0-10v
R2
|
ground

R1 = R2 = 1k ohm

Any suggestion?

You need only R2.
Usually 0-20mA range is moved to 4-20mA or 2-10mA just to avoid line
broke problems when the current is 0 not because of the signal but
becouse of a circuit malfunction.

Vasile

 

[TuT]

[snip]

Usually 0-20mA range is moved to 4-20mA or 2-10mA just to avoid line
broke problems when the current is 0 not because of the signal but
becouse of a circuit malfunction.

Vasile

4-20mA also has the advantage that you have up to 4mA available to power
remote signal processing.