Configuration as a Modbus Master
MVI56-MCM
♦
ControlLogix Platform
Modbus Communication Module
ProSoft Technology, Inc.
Page 39 of 159
July 24, 2008
Label Description
Enable = 1
Causes the module to send the command every time it goes through
the command list.
IntAddress = 5
Writes the data from address 5 of the module memory to the slave
device. Based on the MCM.CONFIG.ModDef configuration, this will
take the data from MCM.DATA.WriteData[5] and write that information
out to the slave device.
Count = 1
Writes 1 register (16 bit) to the slave device.
Node = 1
Issues the Modbus command to node 1 on the network.
Func = 2
Issues a Modbus Function code of 6 to write a single register.
DevAddress = 1040
Function Code 6, DevAddress of 1040 will write to address 41041 of the
Modbus slave device.
4.3.8 Write
Multiple
Registers 4xxxx (Modbus Function Code 16)
Used to write to Modbus Holding Registers 4xxxx, this function code will write
multiple registers to the slave device. The Enable code can be set to a value of 1
for a continuous write, or a value of 2 to write the data to the slave device only
when the data associated with the IntAddress field has changed.
Below is a sample command to write Modbus addresses 41051 to 41060 of node
1 on the Modbus network.
Label Description
Enable = 2
Causes the module to send the command only when the data
associated with the IntAddress of the module has changed.
IntAddress =30
Writes the data from Internal Address 30 of the module memory to the
slave device. Based on the MCM.CONFIG.ModDef configuration, this
will write the data from MCM.DATA.WriteData[30]-[39] to the slave
device.
Count = 10
Writes 10 consecutive registers to the slave device.
Node = 1
Issues the Modbus command to node 1 on the network.
Func = 16
Issues a Modbus Function code of 16 to write Holding Registers.
DevAddress = 1050
Function Code 16, DevAddress of 1050 will write address 41051.
Along with a count of 10, this command writes 41051 to 41060 of the
slave device.
