Hardware Manual

Saia-Burgess Controls AG

Hardware Manual PCD 1 / PCD 2 Series│Document 26 / 737│Edition EN 15│2008-07-22

Communication interfaces

4

PCD7.F150

4.5.5 RS 485 with PCD7.F150, Port #1 (without PCD1.M110)

PCD7.F150:

RS 485 electrically isolated, with line

termination resistors capable of activation, for

socket A

The electrical isolation is achieved with 3

optocouplers and a DC / DC transducer.

The data signals are protected against

surges by a suppressor diode (10 V). The

line termination resistors can be connect-

ed / disconnected with a jumper.

10

11

12

13

14

15

16

17

18

19

J1

OPEN CLOSED

19

18

17

16

14

13

12

11

PCD7.F150

Socket A RX - TX

/RX - /TX

RX - TX

Bus RS 485 /RX - /TX

D

/D

S-BUS

PGNDPGND

PGND

50 VDC

50 VDC

SGND (electrically isolated, must

be connected to the cables shield)

Block diagram:

TXD

RXD

RTS

75176

OPTO-0601

SGND

+5VE

330 Ohm

150 Ohm

330 Ohm

D

/D

+5V

PGND SGND

+5VE

EN

SGND

Transmit

Receive RS 485Driver

DC

DC

Not all manufacturers use the same connection configuration, so the data lines may

need to be crossed.

The potential difference between PGND and the data lines Rx-Tx, Rx- / Tx (and

SGND) is limited to 50 V by a suppressor capacitor.

For installation details, see manual 26 / 740 :

“Installation components for RS 485 networks”.