ProSoft Technology MVI56E-MNETC - Manual (Page 58)

Guide to the MVI56E-MNETC User Manual MVI56E-MNETC ♦ ControlLogix Platform
User Manual Modbus TCP/IP Client Enhanced Communication Module
Page 58 of 183 ProSoft Technology, Inc.
February 3, 2013
MB Address in Device
This parameter specifies the starting Modbus register or bit address in the server
to be used by the command. Refer to the documentation of each Modbus server
device for the register and bit address assignments valid for that device.
The Modbus Function Code determines whether the address will be a register-
level or bit-level OFFSET address into a given data type range. The offset will be
the target data address in the server minus the base address for that data type.
Base addresses for the different data types are:
 00001 or 000001 (0x0001) for bit-level Coil data (Function Codes 1, 5, and
15).
 10001 or 100001 (1x0001) for bit-level Input Status data (Function Code 2)
 30001 or 300001 (3x0001) for Input Register data (Function Code 4)
 40001 or 400001 (4x0001) for Holding Register data (Function Codes 3, 6,
and 16).
Address calculation examples:
 For bit-level Coil commands (FC 1, 5, or 15) to read or write a Coil 0X
address 00001, specify a value of 0 (00001 - 00001 = 0).
 For Coil address 00115, specify 114
(00115 - 00001 = 114)
 For register read or write commands (FC 3, 6, or 16) 4X range, for 40001,
specify a value of 0
(40001 - 40001 = 0).
 For 01101, 11101, 31101 or 41101, specify a value of 1100.
(01101 - 00001 = 1100)
(11101 -10001 = 1100)
(31101 - 30001 = 1100)
(41101 - 40001 = 1100)
Note: If the documentation for a particular Modbus server device lists data
addresses in hexadecimal (base16) notation, you will need to convert the
hexadecimal value to a decimal value to enter in this parameter. In such cases, it
is not usually necessary to subtract 1 from the converted decimal number, as this
addressing scheme typically uses the exact offset address expressed as a
hexadecimal number.
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