Features Of The X27 (Rs 422/485) Interface - Siemens SIMATIC S7-400 Equipment Manual

Product Description

1.4 Features of the X27 (RS 422/485) Interface

The S7-400 backplane bus is a serial data bus via which the CP 440 communicates with the
modules of the programmable controller.
1.4 Features of the X27 (RS 422/485) Interface
Definition
The X27 (RS 422/485) interface is a voltage-difference interface for serial data transmission in
compliance with the X27 standard.
Properties
The X27 (RS 422/485) interface has the following attributes and is in compliance with the
following requirements:
• Type:
• Front connector:
• Max. transmission rate: 115.2 Kbps
• Max. cable length:
• Standard:
• Degree of protection:
Note
With the RK 512 and 3964(R) protocols, the X27 (RS 422/485) interface submodule can only be
used in four-wire mode.
Cables
Siemens offers standard cables in various lengths for point-to-point connection between the
communication processor and a communication partner.
For order information and the length of standard cables are listed in the appendix
"AUTOHOTSPOT".
Fabricating Your Own Cables
If you are fabricating your own cables, there are a few points to take into consideration. The
appendix "AUTOHOTSPOT" of this manual contains information about this topic as well as the pin
assignment of the sub D male connector and the wiring diagrams.
16
Differential voltage interface
15-pin sub-D female with screwed interlock
1200 m at 19200 Bps
DIN 66259 Parts 1 and 3, EIA-RS 422/485, CCITT V.11
IP 00
Point-to-point connection CP 440 Installation and Parameter Assignment
Equipment Manual, 03/2022, A5E00057742-AE