ZU25102A_e.DOC / Mrz-08
Page 8 / 26
3.5.
Serial interfaces
The unit provides a RS232 interface and a RS485 interface, however only one of the two can be
used at a time. Serial communication allows to read out the counting result and to set
parameters and variables by PC, according to need.
5
4
3
2
1
9
8
7
6
GND int.
TxD
RxD
RS232
+5V
T+
T-
R+
R-
RS485
Sub-D-9 (female on unit site)
5
4
3
2
1
9
8
7
6
5
4
3
2
1
9
8
7
6
5
4
3
2
1
9
8
7
6
5
4
3
2
1
9
8
7
6
GND
TxD
RxD
PC
ZU 251
RS232:
Please connect only pins 2, 3 and 5 !
5
4
3
2
1
9
8
7
6
5
4
3
2
1
9
8
7
6
T+
T-
120 Ohms
120 Ohms
RS485- Bus
( 4- wire )
ZU 251
120 Ohms
120 Ohms
R+
R-
T+
T-
R+
R-
5
4
3
2
1
9
8
7
6
5
4
3
2
1
9
8
7
6
T+
T-
120 Ohms
120 Ohms
RS485- Bus
( 2- wire )
ZU 251
