IBM Modbus Plus manual Local Addresses, External Addresses

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Mappings

4.4 Local Addresses

When a mapping is created which allows a PLC to access data within the X-Link, a local address dialog box must be completed. The information required to complete a local address definition is the class of data to access (Coils, Input Status, Input Registers or Holding Registers) and the offset into the data table. If the access is specifying write, Input Status and Input Registers are not available as options.

The data type maps to register numbers as:

Data Type

Register Numbers

 

 

COILS

0xxxxx

 

 

INPUT STATUS

1xxxxx

 

 

INPUT REGISTERS

3xxxxx

 

 

HOLDING REGISTERS

4xxxxx

 

 

where 'xxxxx' represents a decimal number from 1 to 65535.

4.5 External Addresses

Mappings, which require the X-Link to originate commands, require the user to complete an external address dialog box. The external address requires the specification of a route to a remote node as well as a data type and offset.

To route directly to another PLC on the Modbus Plus, simply specify the node number in decimal. If you are routing to a node through any routes, the route is specified as up to five node numbers with periods between them.

To route to an X-Link or SA85 card, the route is specified as node followed by data channel. Data channels are from 1 to 8.

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Contents Version Modbus Plus Link Driver User’s GuideModbus Plus X-Link Driver User’s Guide Contents Modbus Plus X-Link Driver User’s Guide Introduction What is the Modbus Plus Driver?Why Do I Need This Manual? Appears How Do I Use This Manual?Link Technical Support Where Can I Find More Help?Communication Compatibilities RequirementsConfiguration Card Segment Configuration ParametersMappings Data Types and Lengths Source Accesses Destination Accesses External Addresses Local AddressesStatus Counters Troubleshooting Modbus Plus X-Link Driver User’s Guide Driver Cmos Storage Requirements SpecificationModbus Plus X-Link Driver User’s Guide