Operating Instructions

Communication via RS485
5.3 Communication via USS
Fieldbuses
Function Manual, 04/2018, FW V4.7 SP10, A5E34229197B AE
111
5.3
Communication via USS
The USS protocol is a serial data link between a master and up to a maximum of 31 slaves.
A master is, for example:
● A programmable logic controller (e.g. SIMATIC S7-200)
● A PC
The inverter is always a slave.
The maximum cable length is:
● 1200 m for a baud rate up to 38400 bit/s and maximum of 32 nodes
● 1000 m for a baud rate of 187500 bit/s and a maximum of 30 nodes
Additional information on how to connect the inverter to a USS fieldbus:
Integrating
inverters into a bus system via the RS485 interface (Page 110).
5.3.1
Basic settings for communication
Overview
Depending on the inverter, you have the following options for setting communication via the
USS:
● For all inverters with an RS485 interface:
21 "USS Fieldbus"
● For inverters with a CU230P-2 HVAC / CU230P-2 BT
108 "BT Mac 8: USS fieldbus"
For additional information, please refer to the operating instructions of your inverter.
Overview of the manuals (Page 232).
Procedure with default setting 21 "USS Fieldbus"
Proceed as follows to set communication via USS:
1. Activate communication via the RS485 interface using one of the following options:
– With Startdrive during commissioning in step "Default setting of setpoint/command
sources":
21: USS fieldbus
– With the BOP-2 during basic commissioning under step "MAc PAr P15":
FB USS
– Via the parameter number:
p0015 = 21
2. Set the bus protocol via p2030:
p2030 = 1
3. Set the inverter address.