[?]: S7 300 analog input fault discussion

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Mahmoud1992
Posts: 2
Joined: Sun Dec 20, 2020 6:59 pm
Location: Syria

[?]: S7 300 analog input fault discussion

Post by Mahmoud1992 » Sun Dec 20, 2020 7:21 pm

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
Posts: 875
Joined: Tue Dec 26, 2006 5:21 am
Location: Russia

Re: [?]: S7 300 analog input fault discussion

Post by Dfcz » Wed Dec 23, 2020 10:56 am

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

h4rdw4re
Posts: 85
Joined: Mon Feb 25, 2008 8:40 am
Location: Europe

Re: [?]: S7 300 analog input fault discussion

Post by h4rdw4re » Fri Dec 25, 2020 8:47 pm

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
Posts: 2
Joined: Sun Dec 20, 2020 6:59 pm
Location: Syria

Re: [?]: S7 300 analog input fault discussion

Post by Mahmoud1992 » Tue Jan 05, 2021 5:49 pm

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
Posts: 53
Joined: Mon Jan 03, 2011 10:51 am

Re: [?]: S7 300 analog input fault discussion

Post by misa1515 » Wed Jan 06, 2021 9:52 pm

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

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