Festo CPX-M-FB20 Manual page 34

1. Installation
1-20
Checking the fibre optic cable connection
When a fibre optic cable has been installed, you can check
the optical performance in front of the receiving device with a
fibre optical measuring unit (see Appendix A, Tab. A/5).
Proceed as follows:
1. Clean the optical active range of the measuring unit with a
clean cloth free of fluff.
2. Screw the measuring unit adapter onto the measuring
unit.
3. Place the measuring unit with the measuring unit adapter
on the longer of the two remote bus connections on the
Rugged Line plug.
4. Set the measuring unit to 660 nm.
5. Measure the optical performance.
For reliable data transmission, the measured level must
not exceed a value of -3.6 dBm or drop below a value of
-18.0 dBm.
This level takes into account the performance drift of the send
and receive components and a system reserve of 3 dB.
Festo P.BE-CPX-FB20/21-EN en 1202a