Hi friends, from Aug 4th onwards iam getting spikes for analog inputs in our D

Hi friends, from Aug 4th onwards iam getting spikes for
analog inputs in our DCS for a period of 800ms. I throughly
checked every thing, finally i found that the DI, DO's from
MCC panels shields are terminated in the Signal Earth where
Analog Input signals shields are terminated. Is there any
problem with this type of termination?. i checked the
induction voltage from MCC and getting around 25VAC, please
suggest me in this concern. Our plant is 8months old only.
DCS is Siemens Make Simatic PCS7, and the transmitters are
Yokogawa make.

Question Posted / sankarithi

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Hi friends, from Aug 4th onwards iam getting spikes for analog inputs in our DCS for a period of 8..

Answer / sankarithi

Hi Friends only problem is due to earth pit. I throughly
checked every thing, finally i found that the Earth pit
totally became dry. I serviced the pit,Now there is no
spikes.

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