ABB ControlMaster CM50 - CM10 Electrical Connections

ControlMaster CM10, CM15, CM30 and CM50
Universal process controllers and indicators,
1
/8,
1
/4 and
1
/2 DIN 5 MODBUS Communications
IM/CM/C–EN 15
5.3 Two-wire and Four-wire Connection
MODBUS serial communications can be configured as either 2-wire or 4-wire serial links – see Fig. 5.1. The instrument must
be added to the link configuration on the host system – refer to information supplied with the host system.
Fig. 5.1 2-Wire and 4-Wire MODBUS Serial Links
14
15
16
17
18
14
15
16
17
18
Modbus Modbus
Comms
Comms
19
20
21
22
23
19
20
21
22
23
CM10, 15, 30 CM50 CM10, 15, 30 CM50
'A'
'B'
'A'
'B'
Host Computer
Host Computer
2-Wire Connection
4-Wire Connection
Standard Connections
Standard Connections
'A'
'B'
'A'
'B'
Tx+/Rx+
Tx–/Rx–
COM
Tx+
Tx–
Rx+
Rx–
GND
0 V
1.8
 Pull-
down Resistor
1.8 k
 Pull-up
Resistor
+5 V
Tx+
Tx–
Rx+
Rx–
COM
0 V
+5 V
0 V
+5 V
1.8 k
 Pull-up
Resistor
1.8 k

Pull-down Resistor
1.8 k

Pull-up
Resistor
0 V
1.8 k

Pull-down Resistor