Service manual

B - 50
Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 2.0
Appendix B • Vission 20/20 Application Procedures
Test 1
The fi rst test measured the noise on the active net-
work WITHOUT the Phoenix Contact PSM-ME isolator
installed in the network, see Figure B-26. The Phoenix
Contact PSM-ME repeater/isolator was removed from
the circuit and the USB/RS485 convertor was wired di-
rectly to the Vission 20/20 RS485 serial port. The follow-
ing screen capture from the scope shows the amount of
noise on the network signals, see Figure B-27.
Figure B-27. Network Noise
Test 2
The second test measured the noise on the active net-
work with the Phoenix Contact PSM-ME isolator installed
in the network. The following screen capture from the
scope shows the amount of noise on the network signals.
The noise on the signal lines has been signifi cantly re-
duced with the addition of the Phoenix Contact PSM-ME
isolator installed in the network.
Figure B-28. Network Noise with Phoenix Contact PSM-ME Isolator