Rockwell-automation 1769-SDN Compact I/O DeviceNet Scanner Module User Manual de usuario descargar pdf (Pagina 37)

Publication 1769-UM009E-EN-P - August 2009 37

Automatically Configure a DeviceNet Network Chapter 4

The input and output data is mapped into the scanner's I/O data table based

on the device's node address and the configured fixed mapping size. The

DINT-based formula is used with the CompactLogix controller for calculating

the Input or Output data location is:

Input (Output) Offset = [(Node Address) x (Allocation Size)] / 4

The data offset value is used to account for scanners that have a fixed status

field at the start of the input or output data, for example, the 1769-SDN

scanner.

EXAMPLE

When using the default fixed mapping size of 4 bytes, the input data for the devices shown in the example

below is allocated in the 1769-SDN's input table as shown below. Notice node 1 is located in the data map

at DINT location 1, node 2 at DINT location 2, and so on.

Notice that, in this example, node 4 is unused. However, the I/O memory slot remains allocated for it.

01 02 03 05

IMPORTANT

If you are using a MicroLogix 1500 controller with a 1769-SDN

scanner, you must use the following WORD-based formula for

calculating the Input or Output data location:

Input (Output) Offset = ([(Node Address) x (Allocation Size)] / 2) +

Data Offset

In this formula the Data Offset = 66 for Input Offset and 2 for

Output Offset.

1 2 ... 32 33 34 35 36 37 38 39 40 41 42 ... 155 156

Sin comentarios

Rockwell-automation 1769-SDN Compact I/O DeviceNet Scanner Module User Manual de usuario Pagina 37