4. Configuration
98
Data Types
Size [bits]
Description
Coil Writing
1
Writing digital output
Coil Reading
1
Reading digital output
Writing Register
16
Writing analog output
Reading Holding Register
16
Reading analog output
Holding Register with AND
mask
16
Analog output which can be read or written
with AND mask
Holding Register with OR
mask
16
Analog output which can be read or written
with OR mask
Input Register
16
Analog input which can be only read
Input Status
1
Digital input which can be only read
Table 4-50. Data Types Supported in MODBUS RTU Master
Data Start Address:
Data initial address of a MODBUS mapping.
Data Size:
The size value specifies the maximum amount of data that a MODBUS relation can
access, from the initial address. Thus, to read a continuous address range, it is necessary that all
addresses are declared in a single relation. This field varies with the MODBUS data type configured.
Data Range:
This field shows the memory address range used by the MODBUS relation.
Quality Variable:
This field is used to specify a variable which will contain the data of the
MODBUS relation quality.
ATTENTION:
If you use a variable which covers the addresses 5 to10 of a function declared in the Mappings tab,
the reading/writing requests that reach the ends or part of the mapping will be valid.
Example: reading/riting of this function from addresses 1 to 5, only the address 5 is declared. Thus,
only this will receive valid values; the remaining ones will be disregarded as they get invalid values.
Requests Configuration
The configuration of the MODBUS requests (Figure 4-14), follows the parameters described in Table
4-51:
