I/O Communication Characteristics; I/O Data Configuration; Mapping I/O Data - Omron WS02-9094G - V1.0 Operation Manual

I/O Communication Characteristics

3-5

I/O Communication Characteristics

3-5-1

I/O Data Configuration

I/O Data Configuration
I/O Data Range Supported
3-5-2

Mapping I/O Data

I/O Mapping Concept
Default I/O Mapping
Algorithm
90
Each slave device defines its I/O data size, sequence and format by means of
I/O modules, each of which consists of one or more bytes, containing a
PROFIBUS defined coding scheme. The I/O modules can define input data,
or output data or both input and output data. The I/O modules are used to
configure the I/O data exchange process in the Master Unit and also to verify
the amount of I/O data to be exchanged with the slave device.
For modular slave devices the I/O modules are selected by the user from a list
of available modules. The modules usually have to be consistent with the
physical I/O of the slave device. For non-modular slave devices there is only
one I/O module, and can therefore not be selected by a user.
The selected I/O module bytes are sent over the PROFIBUS network to the
slave device at startup, using a Chk_Cfg message. The slave device has to
check and approve the I/O modules sent by the Master Unit, before I/O data
exchange can be established.
The CS1/CJ1W-PRM21 PROFIBUS Master Unit supports up to 4000 I/O
modules, which can define a total of up to 7168 words of input data and/or
output data. The I/O module selection made per slave by the user is also used
to setup the I/O mapping, i.e. the definition of which I/O modules are mapped
to which PLC memory location.
This section discusses the aspects of I/O data exchange between the CS1/
CJ1W-PRM21 PROFIBUS Master Unit and the PLC CPU.
The CS1/CJ1W-PRM21 PROFIBUS Master Unit provides an I/O mapping
concept, based on the I/O module selection for each slave device. Each
selected I/O module can - depending on whether it defines input and/or output
data - be mapped to one of two input and/or output areas. Each of the two
input and output areas can be mapped to any PLC memory area location,
independent of each other. The I/O mapping must be setup using the CS1/
CJ1W-PRM21 Master DTM, as provided with CX-Profibus.
Mapping the I/O modules involves two steps:
• Allocate each I/O module to one or more of the Input/Output areas.
• Allocate each Input/Output area to PLC memory.
When setting up the network, i.e. selecting the slave devices and I/O modules
per slave, all input modules will - by default - be allocated to Input area 1, all
output modules will be allocated to Output area 1. The following rules apply
when allocating the I/O modules to the areas:
• I/O modules are mapped starting at the lowest address of an Input/Output
area.
• I/O modules are mapped in ascending order according to slave device
address.
• I/O modules per slave device, are mapped in the order in which they were
selected, when setting up the slave device.
Furthermore, Input area 1 is by default mapped to CIO 3300, whereas Output
area 1 is by default mapped to CIO 3200.
Section 3-5