Specifications

66I/O Mapping

For standard slaves and modules the generated DUT contains one ARRAY OF WORD element

for the input and one for the output area. The array size is determined by the I/O size of the slave

or module, rounding an odd byte size up to the next word boundary. For the modules of ST1H-PB

slaves the generated DUTs contain module specific elements for I/O data, control, status and

error information.

Item Description

DUT Var. Identifier

Automatically generated name of the global variable instance of the

DUT.

Identifier

Name of the DUT element.

DUT Type

Data type of the DUT element or global variable.

Number Elements

Number of elements. If >1, then the element is an array.

Class

Input (data is transferred from the master to the CPU) or output (data

is transferred from the CPU to the master).

User MIT-Address

Device, to which the I/O point or I/O point array is mapped.

Global Var.

Identifier

Separate global variable name for specific I/O point.

Buffer MIT-Address

The device address of the element within the data exchange buffer.

This buffer has been specified by the user and is used to exchange

the complete inputs and outputs of all slaves with the buffer memory of

the master.

slave specific transfer

has been selected, the device address for

the I/O-area of the slave selected on the left side must be entered

here. If a slave module is however selected on the left side, this

column is write-protected. It shows the calculated device address of

the selected I/O area. On CPU types, where the calculated device

address is actually not accessible, it may still serve as guidance for

locating module I/O points within the transfer device buffer.

Warning:

The buffer MIT-addresses should not be directly accessed. If a 'Copy POU' with the

extended PLC code for slave modules is used, the contents of the DUT variables, which

are generated for all modules, are copied to the buffer devices. Data, which has been

directly written by the application to these devices, is overwritten.

When a module is selected, the user can enter a user device address and/or a global variable

name to an I/O area of the module.