Instrument was failed

[Swng]

dear all,
My factory got some trouble about the instrumentation was failed like pt100 or flowmeter all of them connect to PLC.
And sometime in scada screen will showing #### look like disconnected but actually wiring its OK.
Its happen not only 1 unit but its go around the plant.
I use S7-300 about 10 units.
I was thinking about the surge but I'm not sure,
Do anyone help me for this issue.
thanks you,

 

[roydm]

Swng,
You need to describe the problem better
Pt 100 sensors should not fail due to a surge, they are Non powered devices, what are the symptoms, Ohms wire to wire or wire to ground.
Regards
Roy

 

[sjjata]

Do you use a profibus system?

 

[danw2]

What does the presumed error code #### mean ?
- Invalid sensor value, outside prescribed limits ?
- sensor open circuit detected ?
- sensor short circuit detected ?
- Analog input board not functional ?
- smart diagnostics indicate failure?

Are these failures located on the same AI card?
Are the AI cards universal input (0/4-20, T/C, RTD) or dedicated, like RTD only?

Did all of these failures occur at the same time, like at 03:23 hours on such and such a date?

Are the failures related to analog I/O on the local PLC or associated with transmitting analog field values from PLC to PLC?

What have you done to fix the problem(s)? replaced sensor? fixed wiring? replaced power supply?

Have the fixes worked, or are the input points still broken?