157
saia-pcd.com
Switch cabinet components
5
Switch cabinet
components
4
Consumer
data acquisition
3
Dedicated
room controllers
2
Operation
and monitoring
1
Automation
stations
Use of slaves in the serial S-Net
Slaves can be decentralised input/output modules (RIO = Remote Inputs and
Outputs), external devices (e.g. electronic power meters) or PCD stations.
Bear in mind here the electrical load of the Serial S-Net. RAIL and SAFE
remote input/output modules have high impedance and load the
Serial S-Net only slightly. Up to 100 slaves can therefore be used in
one segment.
If the bus cycle time is critical, fewer than 30 slaves should be
operated in one segment.
Example system design
The RAIL modules can also be mount-
ed in series in an IP 66 housing for
decentralised field assembly. Further
information can be obtained from the
manufacturer Spelsberg, for example.
Limitation owing to the electrical load on the Serial S-Net:
Total PCD systems (incl. master PCD) and RIOs on one serial S-Net branch
Number Number
PCD RIO
0…7
100
8
96
9
92
10
88
11
84
12
80
13
76
Number Number
PCD RIO
14
72
15
68
16
64
17
60
18
56
19
52
20
48
Number Number
PCD RIO
21
44
22
40
23
36
24
32
25
28
26
24
27
20
Number Number
PCD RIO
28
16
29
12
30
8
31
4
32
0
RAIL modules with
Serial S-Net
connection, power pack PCD7.L500 and termination box PCD7.T162
RAIL modules with
Serial S-Net
connection, separate module supply and termination box PCD7.T162
SAFE modules with
Serial S-Net
connection and separate module supply and termination box PCD7.T162
Enable PCD
terminating resistor
After 15 modules the maximum power consumption
must be restarted with an external power supply
24 VDC/AC
Termination box PCD7.T162
Serial S-Net
Serial S-Net
Serial S-Net
24 VDC output voltage
Termination box PCD7.T162
PCD7.L500 power supply (operating
voltage 110…240 VAC)
Serial S-Net
Enable PCD
terminat-
ing resistor
Supply 24 VAC/VDC
PCD
Enable terminating
resistor
Termination box PCD7.T162
Serial S-Net
After 15 modules or after reaching
the maximum power consumption
must be approached with a new
external power supply
