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Isolation requirements from 60 Hz noise on long comm. cable runs

Isolation requirements from 60 Hz noise on long comm. cable runs

Isolation requirements from 60 Hz noise on long comm. cable runs

(OP)
For most industrial computer inputs of digital or analog data, what are the requirements to limit 60Hz induced signals?   Application presumes use of shielded twisted pair cable on the communication (data) circuit, run in proximity to large electrical power lines in non-ferrous ductbanks, for lengths up to 1000 ft.    Will use of rigid steel conduit for the communication cables be sufficient if placed within inches of the power cables?  If not, how much separation is required as a rule?

RE: Isolation requirements from 60 Hz noise on long comm. cable runs

Long runs of analog (4-20ma) signals are problematic. I have even had problems with long runs of digital (descrete) 24 VDC signals. However there are several points:

There are analog input cards with 60Hz filtering.

The more seperation between the analog signal wire and sources of interference the better.

Steel conduit is better than PVC duct banks.

If possible consider remote I/O and run serial communication wiring. This tends to be more resistant to interference.

RE: Isolation requirements from 60 Hz noise on long comm. cable runs

Most of all if you are useing twisted pair sheilded, take extreme care to insure the sheild is grounded to earth at one end only, and can not short to the conduit at any point.


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