[?]: s7 200 analog signal is unstable

kambiz · Post by **kambiz** » Wed Sep 02, 2009 5:31 pm

hi
i need some advice, so help me if someone can!

i use analog input AIW0 from analog module EM235. Signal on the input AIW0 is 0(4) ... 20 mA (0...32000), but that signal is unstable!

Coyote · Post by **Coyote** » Tue Sep 08, 2009 10:59 am

So, what's up. You should make the signal stable, there is no other way. You can also apply filter for analog signals (see the system block).

dsekulic · Post by **dsekulic** » Tue Sep 08, 2009 3:12 pm

Hi,
Maybe You have some interference in vicinity of measuring system. Do You You use screened cable?
regards

xdoit · Post by **xdoit** » Sat Sep 19, 2009 2:01 pm

hi,
You should use STP (Shielded Twisted Pair) cable for that sensor and make sure only one end to be connect to earth.

rgds,

hsiung