What Mesa interface to use for 4-20mA input. Starting with a 7i76e

Hello,

I'm building a 3 (or maybe 4) axis CNC based around a 7i76E. I'm interested in measuring current from various devices and getting that into LinuxCNCs. It looks like most of the appropriate devices (affordable Hall Effect current sensors) output either a 4-20mA signal or a +-4V signal.

From my relatively inexperienced eyes, it looks like I can wire the 4V ones directly into the 7i76E inputs, but that I would need other hardware in order to handle the 20mA signals.
For example, here are two of the devices I'm looking at using:
+-4V
and
4-20mA

So

1. Can I read the fist one directly with a 7I76E?
2. Am I right in thinking that the second would require a 7I47(S)? They are the only cards that appear to mention 20mA signals
3. Do those two cards play well together, or should I be considering something completely different?

Thanks

When I looked at this (for higher currents) I looked at using a ACS758 current sensor coupled with a LM358 amplifier module to step up the voltage.
That would allow reading the voltage on the 7i76e analog inputs. You would have to decide if the 7i76e accuracy was adequate for your needs

A more accurate method would be to use a Mesa THCAD-5 to measure the 5v voltage and send it to an encoder input like we do with plasma torch voltage. the ohmic.comp would give you a code example to work with.
 

A 7I87 would be one solution, This has six +-10V 12 bit resolution analog
input channels and connects to the 7I76E's SSerial expansion port.

Mesa is currently out of stock but more are being built

Thanks for this, very helpful. The 7I87 looks like a great solution. I went ahead and grabbed the one JT has.