Siemens Connecting the Simatic Box PC 620 to other Simatic S5, Point-To-Point Connection

Setting Up and Operating the SIMATIC Box PC 620

3.6Connecting the SIMATIC Box PC 620 to other SIMATIC S5

Point-To-Point Connection

In this section, you will learn how to connect your SIMATIC Box PC 620 to a programming device or S5 programmable logic controller using a point-to-point connection.

You can stablish a point-to-point connection by connecting the

SIMATIC Box PC 620 to another programming device or a programmable logic controller using

SA V.24 connection

SA TTY connection (optional product feature)

Configuring Interfaces with Line Current (TTY, 20 mA)

To ensure reliable data transfer, several factors must be taken into account. The maximum data transfer rate (baud rate) depends on the distance, the type of cable, the pin assignment of the interface and external interference.

You can reduce interference by choosing the right transmission cable and connecting it properly, and by observing the following guidelines:

SUse a shielded cable with a low line resistance (130 W / km) (about 40 W kft) and low capacitance (< 90 pF/m) (about 27 pF/ft). Twisted-pair cables are less susceptible to noise and interference. A low line resistance results in reduced voltage excursions and shorter charge reversal times. The line resistance de- creases with increasing conductor cross-section for the same length of cable.

SThe shorter the transmission link, the higher the maximum possible data transfer rate.

SIf there is an active sender and an active receiver at the same end of the transmission link, the sequence of access priority to the transmission circuit must be taken into account in order to achieve the longest possible transmission link.

SSignal lines and power lines must not run together. Signal lines must be installed as far away as possible from sources of strong interference (for example, 400 V 3-phase power cables).

SThe active TTY interface with a 12 V no-load voltage has been tested on a 100 m (1100 ft) long cable at a transmission rate of 9600 bps in an environment with normal levels of noise fieldstrengthV/mor1V/ft).If a shielded 5 x 1 x 0.14shielded cable is used, reliable transmission is possible over a distance of up to 100 m (1100 ft). The AS511 protocol (only one transmitter at a time) was used for testing.

Note

The interference field of the source of interference is reduced by the square of the distance.

SIMATIC Box PC 620 Manual	3-19
A5E00131465-01