48
Connecting the Control Signals
Section 5-5
5-5-3
Screening
For all signal cables the best results are obtained if the screening is con-
nected to both ends: the VSD side and the at the source (e.g. PLC, or com-
puter). See Fig. 41.
It is strongly recommended that the signal cables be allowed to cross mains
and motor cables at a 90
angle. Do not let the signal cable go in parallel with
the mains and motor cable.
5-5-4
Single-ended or double-ended connection?
In principle, the same measures applied to motor cables must be applied to all
control signal cables, in accordance with the EMC-Directives.
For all signal cables as mentioned in section 5-5-2 the best results are
obtained if the screening is connected to both ends. See Fig. 41.
Note
Each installation must be examined carefully before applying the proper EMC
measurements.
Fig. 41 Electro Magnetic (EM) screening of control signal cables.
5-5-5
Current signals ((0)4-20 mA)
A current signal like (0)4-20 mA is less sensitive to disturbances than a 0-10 V
signal, because it is connected to an input which has a lower impedance (250
) than a voltage signal (20 k
). It is therefore strongly advised to use current
control signals if the cables are longer than a few metres.
Control board
Pressure
sensor
(
example
)
External control
(e.g. in metal housing)
Control consol
Summary of Contents for SX-F
Page 2: ......
Page 14: ...6 Table of contents...
Page 20: ...12 Glossary Section 1 6...
Page 32: ...24 Cabinet mounting Section 2 3...
Page 58: ...50 Connecting options Section 5 6...
Page 72: ...64 Load Monitor and Process Protection 400 Section 7 5...
Page 74: ...66 EMC standards Section 8 1...
Page 266: ...258 System Data 900 Section 11 9...
Page 274: ...266 Maintenance Section 12 3...
Page 284: ...276 Liquid cooling Section 13 12...
