47
Connecting the Control Signals
Section 5-5
5-5-2
Types of control signals
Always make a distinction between the different types of signals. Because the
different types of signals can adversely affect each other, use a separate
cable for each type. This is often more practical because, for example, the
cable from a pressure sensor may be connected directly to the variable speed
drive.
We can distinguish between the following types of control signals:
Analogue inputs
Voltage or current signals, (0-10 V, 0/4-20 mA) normally used as control sig-
nals for speed, torque and PID feedback signals.
Analogue outputs
Voltage or current signals, (0-10 V, 0/4-20 mA) which change slowly or only
occasionally in value. In general, these are control or measurement signals.
Digital
Voltage or current signals (0-10 V, 0-24 V, 0/4-20 mA) which can have only
two values (high or low) and only occasionally change in value.
Data
Usually voltage signals (0-5 V, 0-10 V) which change rapidly and at a high fre-
quency, generally data signals such as RS232, RS485, Profibus, etc.
Relay
Relay contacts (0-250 VAC) can switch highly inductive loads (auxiliary relay,
lamp, valve, brake, etc.).
Example:
The relay output from a variable speed drive which controls an auxiliary relay
can, at the moment of switching, form a source of interference (emission) for a
measurement signal from, for example, a pressure sensor. Therefore it is
advised to separate wiring and screening to reduce disturbances.
Signal type
Maximum wire size
Tightening torque
Cable type
Analogue
Rigid cable:
0.14-2.5 mm
2
Flexible cable:
0.14-1.5 mm
2
Cable with ferrule:
0.25-1.5 mm
2
0.5 Nm
Screened
Digital
Screened
Data
Screened
Relay
Not screened
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...
