Super Systems AC20 - Manual (Page 11)

9
NOTES: NOTES: NOTES: NOTES: NOTES: 1) To avoid electrical shock, connect
power line at the end of the wiring procedure.
2) For power connections use No 16 AWG or larger wires
rated for at last 75 °C.
3) Use copper conductors only.
4) Don’t run input wires together with power cables.
5) When a relay output is used to drive a low power
signal (PLC input, alarm annunciator, etc..) it is
necessary to use an external relay with a gilded
contact.
All relay contacts are protected by varistor against inductive load
with inductive component up to 0.5 A.
The following recommendations avoid serious problems which
may occur, when relay output drives inductive loads.
INDUCTIVE LOADS INDUCTIVE LOADS INDUCTIVE LOADS INDUCTIVE LOADS INDUCTIVE LOADS
High voltage transients may occur switching inductive loads.
Through the internal contacts these transients may introduce
disturbances which can affect the performance of the instrument.
For all the outputs, the internal protection (varistor) assures a
correct protection up to 0.5 A of inductive component.
The same problem may occur when a switch is used in series
with the internal contacts as shown in Fig. 9.
Fig. 9 EXTERNAL SWITCH IN SERIES WITH THE INTERNAL
CONTACT
In this case it is recommended to install an additional RC
network across the external contact as show in Fig. 9.
The value of capacitor (C) and resistor (R) are shown in the
following table.
Anyway the cable involved in relay output wiring must be as far
away as possible from input or communication cables.
R
C
LOAD
LINE
LOAD
(mA)
<40 mA
<150 mA
<0.5 A
C
( µ F)
0.047
0.1
0.33
R
( Ω )
100
22
47
P.
(W)
1/2
2
2
OPERATING
VOLTAGE
260 V AC
260 V AC
260 V AC