37
Twisted pair cable is used to connect RTU de-
vices, e.g. DATAJAMAK 2 x (2 + 1) x 0.24.
The bus cable’s shield (FE) is connected to the
BG connector of the S203. In the master de-
vice the shield can be left disconnected or be
connected to a potential free contact. A 120
Ω terminating resistor is connected to both
ends of the bus.
The factory default for the device’s slave ad-
dress is 10 and the bus speed is 9600 bauds.
If necessary, make changes in the “System
settings”.
Modbus RTU connection:
Compressor
Heating resistor
Sum alarm
Control of the compressor and heating resistor
91
92
Group center
Suply current 230 Vac
230V
ac IN
L
N
2x1.5 S
L
N
Connection of external power source (max. 150VA):
71
72
24Vac input
2x0,8
max. 6 A
24 VAC
~
2x0,8
A1
NO
10 VDC output
C
NC
A2
66
Y4
67
120 Ω
120 Ω
BG
A1
A2
-
+
Master
device
S203
Slave
device
Data
Data
3
5
6
A
BG
B
The controller uses a 230 VAC operating volt-
age, whereby the power supply is supplied to termi-
nals L (91), N (92). In addition, use an external 24VAC
power supply if the power requirement for triac outputs and 24
VAC outputs exceeds 23VA.If you are using an external 24VAC
power supply, we recommend that you use a conventional iron
core transformer in an environment where electromagnetic in-
terference can occur, because the iron core transformer will fil-
ter well external interference.
Other connections
If the external 24 Vac transformer is used in, move
the jumper from right to left. Jumper is above the
terminals 71 and 72.
71 72
External 24 Vac transformer is in use.
Jumper
Explanation
Internal 24 Vac transformer is in use.
57
58
2x0,8
2x0,8
TR3
TR4
A1
NO
24 VAC Relay
C
NC
A2
A1
NO
24 VAC Relay
C
NC
A2
67
