Analog Input problem

[JustinCochran]

Hi,

 

I'm using a V200-18-E1B and I have an analog input from a 4-20 mA amp gage. The problem I have is the reading I get is always a negative number. Instead of seeing 22 it's -22. I have it set up in linerization where x is 204-1023 and y is 0-100 representing a %. I have a common 0V going to 0V on the analog input. I jumpered V and I together and connected one side of the amp gage to that and the other to the 0V. Am I doing something wrong? I keep looking over the specs and how I configured and I'm drawing a blank.

 

Justin

[JustinCochran]

Something to add. When the motor I have is running or not, it always says -24 on output of the linerization block. The input bit is always 0 on the linerization block.

[Alexander]

If the input value is always 0, this indicates that you are not receiving an analog signal from the 4-20 sensor. I would double check both the wiring and that the snap in module is properly receiving 24V power. It does not receive power from the attached PLC and must have either an separate power supply, or jumpered power from the PLC.

[JustinCochran]

All my other inputs and outputs on the snap in module are fine. The power supply isn't the issue. On the analog inputs there is the following for each of the 3:

 

V

I

0V

 

The 4-20 mA sensor clamps around a motor lead and has a "+" and a "-" connection. I think I may have figured out my problem, will have to check next time I'm at work. What I did was go from the + of sensor and go to V and I of ANI0 and the - to 0V. But I don't have any 24VDC + going to it. I'm thinking I need to have the 24VDC + to + of sensor and then the - to I and V and 0V going with the other commons. Now that I think of it, I forgot to give it power. It's usually always something simple, lol.

[sgull]

Hi Justin

 

You dont use the V on the controller when you have a current input, it is used only for voltage input.

You need a 24v supply where the - of the supply is connected to the 0 on the unitronics.

The + of the supply is connected to the + of your 4-20ma transmitter.

The - of your transmitter is connected to "I" on the unitronics.

V is left with no connection.

 

Regards

 

Denis

[Alexander]

Justin,

 

I believe you may have found the solution. For further reference you can also find the wiring for 2,3, and 4 wire sensors for the V200-18-E1B and all of our other I/O modules and PLC's within our technical library on our support page:

 

http://www.unitronics.com/support/technical-library

 

The Snap-In Module specificaitons can be found within the Vision Hardware section.