Serial I/O-Bus

The synchronized serial I/O bus is the I/O data bus for the I/O expansion modules and connects the I/O expansion modules with the Processor Modules or Communication Interface Modules. Through this bus, I/O and diagnosis data are transferred.

Up to 10 I/O Terminal Units (for 1 I/O expansion module each) can be added to one Terminal Base. The I/O Terminal Units have a bus input at the left side and a bus output at the right side. Thus the length of the I/O bus increases with the number of the I/O expansion modules used.

The electrical connection of the I/O bus is performed automatically by telescoping the modules on the DIN rail. The I/O bus provides the following signals:

• Supply voltage of 3.3 VDC for feeding the electronic interface components
• 3 data lines for the synchronized serial data exchange
• several control signals

Attention

The I/O bus is not designed for plugging and unplugging modules while in operation. If a module is plugged or replaced while the bus is in operation, the following consequences are possible

• reset of the station or of the CPU
• system lockup
• damage of the module

Warning

:strong:Removal/Insertion under power

The devices are not designed for removal or insertion under power. Because of unforeseeable consequences, it is not allowed to plug or unplug devices with the power being ON.

Make sure that all voltage sources (supply and process voltage) are switched off before you

• connect or disconnect any signal or terminal block
• remove, mount or replace a module.

Disconnecting any powered devices while energized in a hazardous location could result in an electric arc, which could create a flammable ignition resulting in fire or explosion.

Make sure that power is removed and that the area has been thoroughly checked to ensure that flammable materials are not present prior to proceeding.

The devices must not be opened when in operation. The same applies to the network interfaces.

With its fast data transmission, the I/O bus obtains very low reaction times. Depending on the device and on the version of firmware and Automation_Builder, the following numbers of I/O devices can be connected to the I/O bus.

Device	Version Control Builder/Automation_Builder	Version Firmware	Max. Number of I/O Devices
AC500-eCo PM55x and PM56x (-ETH variants only)	As of V2.0.0	As of V2.0.0	7
AC500-eCo PM55x and PM56x	As of V2.1.0	As of V2.0.6	10
CS31 bus Modules DC551-CS31 and CI592-CS31-HA	All	All	7
CANOPEN Bus Modules CI581-CN and CI582-CN	As of V2.1.0	All	10
PROFIBUS Bus Modules CI541-DP and CI542-DP	As of V2.1.0	all	10
PROFINET Bus Modules CI504-PNIO and CI506-PNIO	As of V2.1.0	all	10
ETHERCAT Communication interface module CI511-ETHCAT and CI512-ETHCAT	As of AB V1.1	As of FW Version V2.0.x	10

General data

Supply voltage, signal level	3.3 V DC ± 10 %
Max. supply current	On request
Type of the data interface	Synchronized serial data exchange
Bus data transmission speed	1.8 Mb/s
Minimum bus cycle time	500 µs 1)
Galvanic isolation	I/O-Bus is galvanic connected to CPU and communication interface logic ciruits. Galvanic isolation of I/O-Bus is I/O module specific. See each module specification for details.
Protection against electrostatic discharge (ESD)	TB5xx, TB56xx: with protection diodes, no ESD discharge allowed on the port.
Max. bus length	1 m

¹) Minimum bus cycle time: This value is valid for all module combinations (from 1 to 10 expansion modules)

Wiring (bus connection)

Bus connection	Left-side and right-side connection from module to module via a 10-pole HE plug (male at the left side, female at the right side)
Mechanical connection	Established by the Terminal Units
Max. bus length	1 m