Darrell L.

I had the same issue a while back... turns out that the SD card reader on my Netduino Plus 2 was the culprit.  The internal spring-switch

was badly bent and not making proper contact (not allowing write operations to the card).

Once I'd bent it back, it worked as it should.

You can inspect for this however YMMV.

Regards,

D.

The part described, XTR111 is a current loop transmitter. It is made by TI, originally Burr-Brown. And they also make a receiver, which called RCV420. 

 

I got interested in them when I found out that HP now Agilent now something else entirely made optoisolators who do the same thing, but for translating digital signals into the methods.

 

And I must say your ideas do hold merit. But please investigate the receiving chip to make sure the generated signals make sense.

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And Chris please check to see why there are four Yeti outside your offices......

Didn't know about the receiver IC... will look into this.  Thanks!

As for the generated signals, they do make perfect sense.  I currently have the circuit in an automated test fixture and have confirmed that the desired programmed currents are indeed what they should be (all via a series ammeter, of course).

Regards,

D.

Very nice, congrats!

To who's reading, this circuit may be useful for current-loop circuit, that is "sending" an analog signal over a very long cable. The more straightforward and intuitive voltage-way leads to pretty high errors.

 

You should have to post it in the "showcase" category: it seems more appropriate.

Thanks, Mario... I'll be sure to post it in the showcase.