Drives With Embedded Fieldbus - ABB ACS310 Quick Start Manual

Quickstart Guide
ABB PLC and drives integration using Modbus RTU
AC500 and AC500­eCo COM port overview
COM Voltage level
Opto‐isolated
(electrically isolated)
Maximum bus cable Acc. to RS485
length
Connection
Termination resistor
built‐in
Termination resistor
size
Pull‐up/pull‐down YES (connect
resistors built‐in with bridges)
Pull‐up/pull‐down
resistor size
Pull‐up/pull‐down Master (CPU)
resistors connection
point
Pull‐up/pull‐down
connection
*) using TK506 RS485 isolator for PM554 / PM564 with index A3 and higher
Drives with embedded fieldbus
The following ABB drives have Modbus RTU embedded:

ACS310

ACS/ACH550

ACS850
Since the built‐in end termination of the drive automatically also activates pull‐up/pull‐down resistors, it is
recommended to skip the built‐in option.
It is recommended to connect a separate end termination resistor to the first node (i.e. the PLC COM interface)
and the last node (i.e. the last drive on the bus).
For connection examples, see chapter "Installation examples".
Modbus RTU
AC500
COM1 COM2
5 V 5 V
YES YES
Acc. to RS485
standard standard
Terminal 9 pole D‐sub
NO NO
120 Ω 120 Ω
NO
470 Ω 470 Ω
Master (CPU)
COM port COM port
Bridges: 1 to External 470
2 and 3 to 4 Ω resistors
AC500‐eCo
COM1 COM2
(optional)
3,3 V 3,3 V
NO NO
optional *)
50 m 50 m
*) Acc to
RS485
standard
9 pole D‐sub Terminal
*) Terminal
NO NO
120 Ω 120 Ω
NO YES (connect
*) yes connect with bridges)
with bridges
270 Ω 270 Ω
Master (CPU) Master
COM port (CPU) COM
port
External 270 Ω Bridges: 1 to
resistors 2 and 3 to 4
‐ 7 ‐
CM574‐RS
COM1=COM2
(see COM1 of
AC500, except pull‐
up/pull‐down)
5V
YES
Acc. to RS485
standard
Terminal
NO
120 Ω
YES (connect with
bridges)
475 Ω
Master (CPU) COM
port
Bridges: 1 to 2 and 3
to 4
PLC and drives integration