V130 Linearization Issues

[sanyc]

Ok guys, first time attempting ladder programming here using a V130-J-R34.  

I am using AN0 to get signal from a 3-wire pressure sensor. Brown/Blue goes to +/- 24Vdc and the black wire is my signal.

I get a 4-20 mA from the sensor and according to the default jumper settings of the V130 the AN0 is set to accept current as input.

I am trying to perform a simple linearization to display how many bars my sensor reads. Since the memory of the analog input is 10-bit this is how I set it up: (see attachment)

The logic is that being a 10-bit memory the max 20mA corresponds to DEC 1023 and min 4mA to DEC 204. Then this is converted to 0-10 bars.

However it does not work. My MI0 reads always zero and the output MI1 is stuck at -25. 

Any ideas here about whats wrong?

Cheers

 

 

[sanyc]

Forgot to attach the rest:

 

 

[Isakovic]

Did you assign MI0 to analog input in hardware configuration? I don't see any other possible mistake in the ladder.

It's probably wiring. Could you post a drawing of your wiring? 0 volts from transmitter supply should be connected to PLC input common to get a current loop.

[Flex727]

This is not a problem with your linearization. Minus 25 is the correct output for an input of 0. If your wiring and other hardware is correct (and you have MI 0 assigned to AN 0) you should always get a minimum value of 204 at MI 0.

[Kikis]

If you have linked MI0 to AN 0 and your wiring is correct then it should work.

 

[Ausman]

I agree with Isak and Flex that it simply looks like you haven't assigned the physical input to MI0, or there is a simple wiring issue.

I've posted because, just FYI, you might like to look at this post with my calculator.

cheers,

Aus

[sanyc]

Thank you all for the replies. I had the MI0 link to AN0 in the hardware configuration.

The problem turn out to be the pressure sensor I was using. I used another LVDT sensor and it worked great, thanks.

[Ausman]

Thanks for getting back to us all Sanyc with your result.  All too often the advice given on the forum is left unanswered.

Aus