AC500-eCo CPU as S500 remote I/O

When the AC500-eCo compact CPU is used as

remote I/O, it can be programmed with  Automa

tion Builder for local intelligence while communi

cating via the open protocols Modbus TCP or

Modbus RTU with a CPU that will then be the

master of this intelligent remote I/O station. The

AC500-eCo CPU can be expanded by I/O modules

from the S500 and S500-eCo range.

S500 remote I/O with Modbus TCP

ABB provides a configurator in the Automation

Builder tool, which allows the configuration of

Modbus TCP I/O stations with the communica

tion interfaces CI521-MODTCP or CI522-MODTCP

in the same style as the AC500 configuration. For

larger applications a Bulk Data Manager tool can

be used. The configuration can be stored in the

communication interface, which allows using

the configured station with any PLC or PC that

supports Modbus TCP. This e.g. allows the use

directly on other controllers or monitoring

systems as e.g. ABB Ability™ Data Center Auto

mation or external systems.

Thanks to the Modbus feature that allows

several masters to exchange data with the same

slave, it is possible to use the I/O station as

shared devices with up to 10 PLC CPUs.

The Modbus masters can access the process data

of the I/O stations in two different ways:

• Fixed mode: each I/O module in the station

uses a separate register address range, which

requires separate Modbus read/write opera

tions for the modules in the station.

• The dynamic mode allows to pack the data of all

I/O modules in the station in one data structure

that can be exchanged in one single read/write operation.