Siemens SICAM Q100 7KG95 Series Manual page 384

14 Technical Data
14.1 General Device Data
Recommended Termination of the RS485 Interface (Connector J)
The RS485 bus requires at least the bus termination shown in the figure below, with pull-up/pull-down resistors:
DC +5 V
Figure 14-1
The bus termination must be respectively carried out at the first and last RS485 device interface of the bus. No
terminating resistor may be used at all other devices in this line.
Siemens recommends the use of a bus termination plug with integrated (activatable) resistors in accordance
with figure 14-1, for example plugs with 35°-cable outlet type 6ES7972-0BA42-0XA0. Use a 2-wired, twisted
and shielded cable (see chapter 2.2). In case of outdoor assembly Siemens recommends a rodent protection.
You can find current installation material at SIEMENS IS in the "Catalog for Industrial Communication", chapter
"PROFIBUS", see also:
https://www.automation.siemens.com/mcms/automation/en/industrial-communications/Pages/Default.aspx.
The 9-pin D-sub socket of the RS485 interface is connected as follows:
Pin No.
1 Shield
2 Not assigned
3 A
RS485 connection pin A
4 Not assigned
5 GND
(towards DC +5 V)
384
390  220 
Bus termination
A
Termination of the RS485 Interface
Assignment
390 
B
Pin No.
6 DC +5 V
Supply voltage for terminating resistors
(max. 100 mA)
7 RTS
Direction control
(if required for an external conversion)
8 B
RS485 connection pin B
9 Not assigned
SICAM Q100, 7KG95xx, Device Manual
E50417-H1040-C522-A6, Edition 06.2019
GND
Assignment