ProSoft MVI56E-MNETCR User Manual page 54

Configuring the MVI56E-MNETCR Module
User Manual
Modbus Function
1, 2, 3, 4, 5, 6, 15, or 16
This parameter specifies the Modbus Function Code to be executed by the
command. These function codes are defined in the Modbus protocol. The
following table lists the purpose of each function supported by the module. More
information on the protocol is available from www.modbus.org.
Modbus Function Code
1
2
3
4
5
6
15
16
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)
Page 54 of 161
Modbus TCP/IP Multi-Client Enhanced Communications Module for Remote Chassis
Description
Read Coil Status
Read Input Status
Read Holding Registers
Read Input Registers
Force (Write) Single Coil
Preset (Write) Single Register
Force Multiple Coils
Preset Multiple Registers
MVI56E-MNETCR ♦ ControlLogix Platform
ProSoft Technology, Inc.