APV_CU4plus_AS-interface_UK-3_062019.indd
UK
Control Unit
CU4plus AS-interface
Instruction Manual UK-3
APV
9
2. Safety Instructions
2.7.5. Increase in interference resistance
- The connection „Schirm“ (shield) at the AS-i power supply unit
must be connected directly and with good RF characteristics with
the potential equalization of the machine or plant. This is not a
grounding measure for safety reasons, but a functional grounding
so that the AS-i line can be operated symmetrically against
the earth. If a shielded cable is used, the cable shield must be
connected there - and there only, as well.
- A good symmetrie must also be observed towards other electrical
sources of interference (speed-controlled actuators, welding units
etc.). The length of the connecting cables between the active slaves
(CU4, CU4plus etc.) and the proximity switches connected to them
must be limited to max. 2 m.
- When high electrostatic charge is expected (e.g. polishing
machines, injection moulding machines, wrapping foils for plastic
materials etc.) it may be required to take additional protective
measures, such as the installation of arresters for static loads.
2.7.6. May the AS-i cable be laid in parallel to power cables?
- Although the communication via AS-i cable is not sensitive to
EMC, it should be laid separately from line cables - also in control
cabinets.
- Maximum distance to potential sources of interference (e.g.
frequency converter) must be observed.
- Every AS-i wiring harness should have its own cable, i.e. AS-i
cables should not be laid together with other cables in the same
common cable.
- If it is required to lay single conductors (e.g. in control cabinets),
parallel conductors must be laid. In case of standard stranded wires,
lay and twist single coductors together.
