Siemens SINAMICS V20 User Manual

SINAMICS V20 Converter
Operating Instructions, 10/2019, A5E34559884-012
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Communicating with the PLC
7
The SINAMICS V20 supports communication with Siemens PLCs over USS on RS485. You
can parameterize whether the RS485 interface shall apply USS or MODBUS RTU protocol.
USS is the default bus setting. A screened twisted pair cable is recommended for the RS485
communication.
Make sure that you terminate the bus correctly by fitting a 120 R bus termination resistor
between the bus terminals (P+, N-) of the device at one end of the bus and a termination
network between the bus terminals of the device at the other end of the bus. The termination
network should be a 1.5 k resistor from 10 V to P+, 120 R from P+ to N- and 470 R from N-
to 0 V. A suitable termination network is available from your Siemens dealer.
7.1 USS communication
Overview
One PLC (master) can connect a maximum of 31 converters (slaves) through the serial link
and control them with the USS serial bus protocol. A slave can never transmit without first
being initiated by the master so that direct information transfer between individual slaves is
not possible.

Siemens SINAMICS V20 Specifications

General

Power Range	0.12 kW to 30 kW
Overload Capacity	150% for 60 seconds
Protection Class	IP20
Storage Temperature Range	-40°C to +70°C
Altitude	Up to 1000 m without derating
Input Voltage	3AC 380 V to 480 V
Output Voltage	0 V to Input Voltage
Control Modes	V/f control
Ambient Temperature Range	-10°C to +60°C
Relative Humidity	5% to 95%, non-condensing
Communication Interfaces	Modbus RTU
Braking Resistor	Optional external