Intermitent stop reading due to cable induction in cp1w

[sergio garcia 0]

Im trying to control a baldor VFD trough modbus RTU with cp1h/cp1wcif12 using the solution posted here which for me works really fine but the problem comes when I turn on the motor (500hp 440v), the cable gets induced and adds noise to the communication causing errors when reading. I already try to use shielded cable and it gets better but still causing errors. In the solution posted in the link above shows how to connect the cp1w-cif12 by connecting only SDA- and SDB+. So my question is, should I connect FG to the VFD rs-485 ground as well to reduce that noise? Any suggestions are welcome

[sbaum 0]

Connected the cable shield to FG at each end. I've run into almost an identical issue in the past where the installer only connected the shield on the one end. Connecting it on both ends like the drawing in the manual solved the issue. See page 705 in the Manual W450 CP1H Operations Manual