Concept
Automatic Device Addressing on the I/O Bus
Each device on the I/O bus can detect its order in the chain of connected devices and assigns itself an address accordingly. This auto-addressing feature is provided by the terminal base backplane of the Central IO modules, the AS-P server, and the PS-24V power supply. The AS-P-3 server differs in that it is a one-piece device, without a terminal base, but the addressing works the same as for the two-piece devices.
In EcoStruxure Building Operation WorkStation, you create a logical Central IO module to be associated with the physical Central IO module on the I/O bus. You specify the Central IO module type and name. Initially, the module ID is Null, which means that the Central IO module is non-operational. You assign a module ID that is equal to the address (position) of the Central IO module on the I/O bus. You can configure the module ID either when you create the logical Central IO module or later. When the Central IO module is plugged into the system at the intended position on the bus, the EcoStruxure Building Operation software automatically associates the physical Central IO module with the logical Central IO module that has a matching module ID and type.
The backplane generates a 5-bit address corresponding to the order (position) of the terminal base in the chain and passes this address through the I/O bus to the electronics module installed on the terminal base (base plate). For more information, see Backplane Board .
The leftmost device in the chain gets the address (position) 1. The next device gets the address 2, and so on, up to 32.
Position 1 is reserved for a power supply. Position 2 is reserved for an automation server. For more information, see I/O Bus Restrictions .
Although the power supply gets an address, the device does not use it.
When you replace an electronics module, the new module automatically picks up the same address. If you remove an electronics module from its terminal base, the addresses of the following devices are not affected.
The following figures show two examples of device addressing with different automation server:
AS-P server
AS-P-3 server
Position 1 is not used when the automation server is an AS-P-3 server.
Hardware Overview
Terminal Bases
Backplane Board
AS-P-3 Servers
I/O Bus Restrictions