30
saia-pcd.com
PCD
3
Automation stations – Saia PCD3
+18 V
0V
GND
+24 V =
0V
L N
L
N
±15%
±20%
24 V
DC
19 V
AC
Grounding and connection plan
Grounding and connection concept analogue inputs that are not electrically isolated (PCD3.W2x0, PCD3.W3x0)
Saia PCD3 power supply and connection concept
It is generally recommended to use robust
and interference-resistant SBC power supply
units with 24 VDC output. See Chapter 5.1
for available types.
Connection concept for PCD3.W2x0
The reference potential of signal sources must be wired to a
common GND distributor at the “–” terminal
External power supply
A two-way rectified supply can be used for most modules.
The following modules must be connected to smoothed 24 VDC:
PCD3. H1xx, H2xx, H3xx, PCD7.D2xx
Connection concept for PCD3.W3x0
The reference potential of voltage and current inputs must be
wired to a common GND distributor at the
“–”
terminal. Tempera-
ture sensors must be wired to a common GND distributor at the
“
COM
”
terminal. The module PCD3.W380 has a 2-wire connection
for the inputs and requires no external GND distributor.
Signal sources (such as temperature sensors) should be connected direct to the input module wherever possible.
To obtain optimum measurement results, avoid connection to a ground bar. Additional external GND connections to the sensor signals may
result in equalising currents which distort the measurement.
If shielded cables are used, the shielding should be continued to a ground bar.
The zero potential (GND) of the 24 V supply is connected to the
GND and the controller’s grounding terminal. If possible, this
should be connected to the ground bar with a short wire (<25 cm)
with a cross section of 1.5 mm
2
. The same applies to the negative
connection to the PCD3.F1xx or the interrupt terminal.
Any shielding of analogue signals or communication cables
should also be brought to the same grounding potential,
either via a negative terminal or via the ground bar.
All negative connections are linked internally. For flawless
operation, these connections should be reinforced externally
by short wires with a cross section of 1.5 mm2.
Transformer min. 50 VA
CONTROLLERS
2.5 mm
2
2.5 mm
2
W...
A...
E...
0 V +24 V
DC
Erdungsschiene
max. 25 cm
min. 2.5 mm
0...10 V
Pt/Ni 1000
Erdungsschiene
Masseanschluss PCD
Verteiler
„V“ und„C“
Verteiler
„Temp.“
Signalquelle
Signalquelle
Mess-
widerstand
Mess-
widerstand
9 8 7 6 5 4 3 2 1 0
-
E7 E6 E5 E4 E3 E2 E1 E0
-
PGND
COM
0...10 V
Pt/Ni 1000
max. 25 cm
min. 2.5 mm
Erdungsschiene
Abgeschirmte
Kabel
Signalquelle
Signalquelle
Masseanschluss PCD
Mess-
widerstand
Mess-
widerstand
Verteiler
-
PGND
9 8 7 6 5 4 3 2 1 0
-
E7 E6 E5 E4 E3 E2 E1 E0
