
Pin
Signal
Interface
Description
1
9
1
Term. P
RS-485
Terminator P
2
RxD/TxD-P
RS-485
Receive/Transmit, positive
3
RxD/TxD-N
RS-485
Receive/Transmit, negative
4
Term. N
RS-485
Terminator N
5
RTS
RS-232
Request to send (output)
6
TxD
RS-232
Transmit data (output)
7
SGND
Signal Ground
Signal Ground
8
RxD
RS-232
Receive data (input)
9
CTS
RS-232
Clear to send (input)
Table 18: Protocols:
No.
Protocol
Description
COM1
1
Online access
Online access for IEC 61131-3 programming via serial driver
2
Modbus
Modbus RTU, master or slave
3
ASCII
Any protocol with FB COM_SEND, COM_REC
4
SysLibCom
Support for blocks contained in the SysLibCom.lib library
5
Multi
Switch between two protocols (Online access, Modbus, ASCII,
SysLibCom) using the block COM_SET_PROT
6
CS31 bus
CS31 bus master
7
RCOM/RCOM+
ABB remote protocol RCOM or RCOM+ (only available as sepa-
rate communication module CM574-RCOM)
COM2
1
Online access
Online access for IEC 61131-3 programming with serial driver
2
Modbus
Modbus RTU, master or slave
3
ASCII
Any protocol with FB COM_SEND, COM_REC
4
SysLibCom
Support for SysLibCom.lib library blocks
5
Multi
Switch between two protocols (Online access, Modbus, ASCII,
SysLibCom) using the block COM_SET_PROT
Bus Cable for RS-485
Bus line
Construction
2 cores, twisted, with common shield
Conductor cross section
> 0.22 mm
²
(24 AWG)
Twisting rate
> 10 per meter (symmetrically twisted)
Core insulation
Polyethylene (PE)
Resistance per core
< 100
Ω
/km
Characteristic impedance
ca. 120
Ω
(100
Ω
...150
Ω
)
Capacitance between the cores
< 55 nF/km (if higher, the max. bus length must be reduced)
Terminating resistors
120
Ω
¼ W at both line ends
Device Specifications
Communication Modules (AC500 Standard) > CM574-RCOM for RCOM/RCOM+
2019/04/17
3ADR010121, 13, en_US
96