Siemens SINAMICS S120 Series Function Manual page 168

Communication via Modbus TCP
6.1 Overview
General information about communication
Communication with Modbus TCP is established via the Ethernet/PROFINET interfaces:
● X150
For Modbus TCP with a CU320-2 PN or CU310-2 PN.
● X1400
For Modbus TCP with a CU320-2 PN or a CU320-2 DP via a CBE20.
Precisely one Modbus connection can be established. A simultaneous connection via the
interfaces X150 and X1400 is not possible and is acknowledged with alarm A08555(1).
However, you can use one interface for Modbus TCP, and the other as PROFINET interface.
Drive object that can be addressed via Modbus
With Modbus TCP, you always address the first control-drive object from the list of drive
objects (p0978[0]). A servo or vector drive object must be in this parameter.
● However, Modbus TCP is only activated if, under p0978[0], there is a drive object that is
supported by Modbus TCP.
● If p0978[0] does not contain a valid drive object, then establishing communication is
acknowledged with alarm A08555(2).
Diagnostics LEDs in Modbus TCP
Diagnostics states are shown as follows using LEDs with Modbus TCP:
● X150: "PN" LED
● X1400 (CBE20): "OPT" LED
The following states can be displayed by these LEDs:
Color
Green
Green
Red
166
State Meaning
Continuous Connections and setpoints are OK.
light
Flashing light Connection is OK, but no setpoints (dependent on timeout).
Flashing light No connection or setpoint timeout.
2 Hz
Function Manual, 12/2018, 6SL3097-5BD00-0BP0
Communication