Appendix A - Modbus Control Via Remote Operator; Termination Resistors - Danfoss MCD 200 Installation Instructions Manual

Appendix A - Modbus Control via Remote Operator

11. Appendix A - Modbus Control via Remote
Operator
To control a soft starter via an RS485 serial communications network using the Remote Operator,
connect the Remote Operator to the network as described in the following sections.
11.1. Grounding and Shielding
Twisted pair data cable with earth shield is recommended. The cable shield should be connected to
a GND device terminal at both ends and one point of the site protective earth.

11.2. Termination Resistors

In long cable runs prone to excessive noise interference, termination resistors should be installed
between the data lines at both ends of the RS485 cable. This resistance should match the cable
impedance (typically 120 Ω). Do not use wire wound resistors.
Network Master
RS485
GND
11.3. RS485 Data Cable Connection
Daisy chain connection is recommended. This is achieved by parallel connections of the data cable at
the actual device terminals.
11.4. Remote Operator RS485 Network Connection
Specifications
Input impedance:
Common mode voltage range:
Input sensitivity:
Minimum differential output voltage:
11.5. Using the Remote Operator with MCD 200
Remote Operator RS485
B8
120
120
B6
B7
GND
1.5 V (with max loading of 54 Ω)
MG.17.F5.02 - VLT® is a registered Danfoss trademark
B3
120
120
B1
B2
GND
12 kΩ
- 7 V to + 12 V
± 200 mV
MCD Modbus Module Instructions
Soft Starter
(Module) RS485
68 (B8)
69 (B6)
61 (B7)
GND
12