Operating instructions

Functions
5.11 Operation in fieldbus systems
CU240S and CU240E Control Units, FW 3.2
Operating Instructions, 03/2009, A5E02440075B AA
153
CAUTION
A difference in the ground potential between the master and slaves in an RS 485 network
can damage the inverter Control Unit. You must make absolutely sure that the master and
slaves have the same ground potential.
SUB D connection on the CU 240S (pin assignment)
The CU240S Control Units are equipped with a 9-pole SUB D socket for connecting the
inverter via an RS 485 interface. A standard 9-pole SUB D connector with a 180° cable outlet
can be used for the USS connection via RS 485.
Table 5- 67 Contact assignment of the 9-pole SUB D socket
Con
tact
Designation Description
1 - Unused
2 - Unused
3 RS 485P Receive and transmit signal (+)
4 - Unused
5 0 V Ground reference
6 - Unused
7 - Unused
8 RS 485N Receive and transmit signal (-)
9 - Unused




X Shield
(housing)
Equipotential bonding
Cable lengths and number of devices
Table 5- 68 Max. no of devices and cable length
Baud rate in bit/s Max. no. of devices Max. cable length
2.400 … 93.750 32 1200 m
115.200 (max. baud rate) 30 1000 m