[?]: S7 300 analog input fault discussion

[Mahmoud1992]

Hello everybody
It is my first time here and i am pretty excited to discuss automation things with you all
What is important is some fault with plc s7 300 happend with me and i did not really find the solution to this problem until the moment
and i find it really intresting topic for all of those people working in this domain

The problem is that i have a plc s7 300 with analog input module sm331 with eight chanels
And there are 8 thermocouples with 4-20mA tmt128 endress and hauser temperature transmitter attached to this module
The thing is that every thing is ok
-the transmitters -the thermocouples every thing and the hmi in the central showing *****
instead of giving the right temp measurment so i trully apreciate any idea about this fault
And thank you all

[Dfcz]

Hello Mahmoud!
Describe the problem. So it is not clear.

[h4rdw4re]

Hi Mahmoud,
Firstly you need to check is everything ok with readings in PLC.
Do you check mA to the channel inputs?
If you have right values on transmitter display and your plc program scaling then you should move to the HMI and its connection to the plc.
What I'm saying is to do basic diagnostic and then came back with your results.
It would be nice if you tell us what HMI you are using and other details.
Happy new year and all the best.

[Mahmoud1992]

Thank you a lot
Every thing ids ok believe me i have done every basic diagnostic you could imagine and there is no problem
The hmi is a pc based hmi
I have doubts that it is a noise or ground loop problem but i need someone to discuss it with

[misa1515]

Hi,
maybe try to share project and with screenshots (HMI screens, etx.) for show what is wrong or not working like is awaiting.