Introduction

The 171 CBU 78090, 171 CBU 98091 and 171 CBU 98091 processors support an I/O-Bus containing up to 32 Momentum devices. The I/O-Bus supports up to 256 input words, and 256 output words.

Monitoring I/O-Bus Health

The processor monitors the health of each module on the I/O-Bus, and stores health data in 2 system registers: %SW128 and %SW129. Each bit represents the health of a module on the I/O-Bus, as follows:

  • %SW128.0 stores the health of the module at address 1

  • %SW129.15 stores the health of the module at address 32

A bit value of 1 indicates a module is healthy.

I/O-Bus Branching

The processors support the use of 170 BNO 671 00 branch interface modules to create a single level of branches on the I/O-Bus.

NOTE: You can create multiple branches using 170 BNO 671 00 branch interface modules, provided those branches are at the same level. You cannot create a second level of I/O-Bus branches by adding a 170 BNO 671 00 branch interface module to a branch created by another 170 BNO 671 00 module.

Creating the I/O-Bus

To create an I/O-Bus, follow these steps:

Step

Action

1

In the Project Browser , navigate to and double-click the Project > Configuration > I/O-Bus node:

The I/O-Bus window opens.

2

In the I/O-Bus window, right-click an empty connection point to display the context menu:

3

Select New Device... to open the New Device window.

4

In the New Device window, do the following:

  1. Select a device from the list.

  2. Enter a Topological Address for the selected device.

  3. Click OK.

NOTE:

  • The Drop end communicator setting is automatically set to the 170 INT 110 03 Interbus adapter.

  • The Topological Address is also referred to as the “drop number”, and defaults to the next lowest available address, from 1...32.
 
NOTE: In place of steps 3 and 4, above, you can instead select a device in the Hardware Catalog and drop it onto an empty connection point. The following version of the New Device window opens:

In this window, enter a Topological Address and then click OK.

5

In the I/O-Bus window, the selected device–in this example the 170 ADI 350 00 module–is added:

In the Project Browser , the new I/O base, and communication module appear as a node on the I/O-Bus:

Click File > Save to retain your edits.