Channel problem on analog input 1756-If6h

[edhoy86]

Good evening, just a dump question, I’ve configured channel no 13 with scalling as attached, then shown not linear reading, even when i simulate with current injector with 0 mA, the raw input value is 2600. My question is this faulty channel? Because i dont see any fault on configuration channel. Thanks for your valuable advice.

 

[danw]

You've configured it for 4.0mA low signal, so your 0mA source is way out of range.



What does it read when you source 4.0mA and 20.0mA

 

[edhoy86]

When i inject 4 mA the raw input value is 10127, then for 20 mA the raw input value is 32017

 

[doctord]

are you using Hart?

 

[drbitboy]

I think there are three possibilities:

1. the channel is faulty, as you are asking
2. the injected current signals (0mA, 4mA, 20mA), when actually measured, are not as assumed (e.g. 0ma "injected" is actually 5.3mA at the module; 4mA "injected" is actually 9.06mA).
   1. Is crosstalk with another channel possible?
   2. Is the wiring correct?
3. the values (2600, 10127, 32017) being read are not the engineering values from channel 13 e.g.
   1. they are from another channel
   2. they have been re-scaled
   3. etc.

Are you able to verify the injected signals i.e. with a DMM or similar?

Does anything change if the [Enable Hart] box is unchecked?

Where are you reading the 2600, 10127, and 32000 engineering values (you call them raw, but they are engineering values even if the represent the raw counts).

 

[edhoy86]

are you using Hart?

Yes i check the box for hart

 

[edhoy86]

I think there are three possibilities:

1. the channel is faulty, as you are asking
2. the injected current signals (0mA, 4mA, 20mA), when actually measured, are not as assumed (e.g. 0ma "injected" is actually 5.3mA at the module; 4mA "injected" is actually 9.06mA).
   1. Is crosstalk with another channel possible?
   2. Is the wiring correct?
3. the values (2600, 10127, 32017) being read are not the engineering values from channel 13 e.g.
   1. they are from another channel
   2. they have been re-scaled
   3. etc.

Are you able to verify the injected signals i.e. with a DMM or similar?

Does anything change if the [Enable Hart] box is unchecked?

Where are you reading the 2600, 10127, and 32000 engineering values (you call them raw, but they are engineering values even if the represent the raw counts).

Alright ill give u the update, but if i edit by online to uncheck the (enable hart) should no problem??, like interference with other channel or controller??