Hi I'm new here and also new at my job. I hope you understand my terms.

I was having a problem identifying on what is being faulty in our current set-up. By the way this system is functional until we noticed that the process monitoring in Operator Stations and HMI are not anymore available/no data.

In this particular AI module we are using all 8 channels from 0-7, 5 channels are found to be not functioning properly.

Channel 0 is a level sensor, Channel 4,5,6,7 are pressure sensors

For now here is my as found conditions in both PLC side and sensor side.

Injected 8mA to all 5 channels while temporarily disconnecting the sensors, and performed module monitoring for HEX values.

Channel 0,4,5,6,7 - from W#16#8000 to W#16#1C3F.

Channel 0 - data changes in HMI and Operator Stations (level monitoring changes or has data upon injecting a certain current signal.

Channel 4,5,6,7 - No value in both HMI and OS.

Upon checking module information's diagnostic buffer these events are active:

1. ADC/DAC error

2. Missing external voltage

3. Module without parameters

and below that is

ADC/DAC error

Internal error, Incoming event.

When all sensor are connected to the module

Level sensor - no display but when I tried to power it using a field communicator the sensor's status is okay and display in the sensor is available.

Pressure sensors - All pressure sensors have display but no data in HMI/OS.

And also I tried to replace the AI module but same problem is encountered.

I have attached captured images for reference.

Thanks :D

I encountered similar problem before, i replaced the pressure transmitter and finally solved this problem. 

someone told me this maybe circuit impedance not matched, so I suggest to install a signal barrier (P+F) between AI input and field sensor. maybe it can work.