Rockwell Automation Allen-Bradley Compact 5000 Series User Manual page 87

Table 23 - Modbus Slave Module Definition Parameters
Parameter
Register Type
Data Type
Register Start Address
Register Length
Data Index
Definition
• Disabled (default)
• Coils
• Discrete Inputs
• Input Registers
• Holding Registers
• BOOL
• INT
• REAL
• 0...65535
(default = 0)
• Dependent on Data Type
– BOOL: 1...128
(default =1)
– INT: 1...100
(default = 1)
– REAL: 1...50
(default = 1)
Location of data in the output or input tags depending on the register type defined.
For more information, see the following section on
Data Index
This value indicates the offset of the register type address in controller tags that
allow the serial module to read or write required data to or from the controller.
Each register type has a predefined array size that can be used for the Modbus
Slave as indicated in the
Holding register has the limit of 100 INT. The array size is 0...99 and the Data
index is 0...99 when the Holding register is used depending on the size and the
location where you want to store the information.
If you exceed the data limit, an error can occur. This error would appear as
in Figure 28.
Figure 28 - Data Index Error
Rockwell Automation Publication 5069-UM003B-EN-P - January 2020
Compact 5000 I/O Serial Module Configuration
Data Index.
Modbus Slave Address Table
Chapter 4
Limits. For example, a
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