Analog 4-20mA input is incorrect

[vken]

Hello,

I got a V130 -33-TR6 to read some 4-20mA analog sensors.

It looks that the input MI doesn't response on what I had in mind.  The values for 0 (Zero) instead of 4mA is 206 in the selected MI and the linear conversion is hard because it looks out of range from the very first time.  At the Current Transformer for instance there is no current  flow and the result should be 0 Amps.

the sensors are 2 wires. so the (-) is going to the input and the (+) is going to the 24V

check out the sc shots. 

what do you think that I'm doing wrong?

[Flex727]

I don't think you're understanding how an analog input works. Your analog input has a 10-bit resolution (or 1024 units). The number that you get in the MI associated with the input will range from 0-1023. For 4-20mA, it will range from 204-1023.

Use 204 & 1023 in your linearization for X1 & X2 and you'll find it works better.

[vken]

respect!

analog is something new for me and I looked in the help before that but I didn't got it right.

for example. how do I know my input resolution if it's 10, 12 or 14 bits? is that plc hardware or it has to do also with the sensors?

thank you for your help!

 

 

[Flex727]

 

2 minutes ago, vken said:

how do I know my input resolution if it's 10, 12 or 14 bits?

Unitronics publishes specs online for all of their hardware. Just look it up at https://unitronicsplc.com/