CPU 72x
24.05.2019
page 11
1.4.3.2
RS-232C
The serial interface RS-232C can be used as data or programming interface.
The connection of the RS-232C interface ensues via the 3 pole connecting terminal (RXD,
TXD and COM).
The maximum bit rate is 38.4
kbit/s.
RS-232C
CPU 723-T, CPU 725-LT/LTH and CPU 727-T/TH
Galvanic separation
RS-232C
logic
Yes
1)
RS-232C
CAN
Yes
1)
RS-232C
UC
Yes
1)
RS-232C
ground
Yes
1)
Test voltage
560
Vac, 800
Vdc
Bit rates
setting via DIP switch S1 and/or software
Driver
Level according ISO
11898 standard
1)
simple insulation
Fig.10: RS-232C wiring
1.4.3.2.1
Installation Remarks
To fulfill the EMC standards (89/336/EEC and EN
50081-2/EN
50082-1) the following point
is to consider at wiring:
RS-232C cable screening to connect on a large area by means of the strain reducing clip
of the CTA 703-T.
IMPORTANT
Do not connect screen on the peripheral side (e.g. PC) with the ground.
Tx
D
Rx
D
CO
M