MVI56E-MCMR ♦ ControlLogix Platform Configuring the MVI56E-MCMR Module
Modbus Communication Module with Reduced Data Block User Manual
ProSoft Technology, Inc. Page 65 of 223
Read Coil Status 0x (Modbus Function Code 1)
Modbus Function Code 1 reads the Coils addressed at 0001 to 9999 from a
slave device. These are bit values that are read using Modbus Function Code 1,
and can be written to using Function Code 5 or 15. Within a Slave device, this is
an individual bit value. Thus, the Internal Address field must be defined down to
the bit level within your MasterCmd.
The following illustration shows a sample command to read Modbus addresses
0321 to 0480 from Modbus Slave Device Address 1.
The module will send the command every time it goes through the
command list.
Places the data read from the slave device into the module at
address 16320. Internal Address 16320 of the module memory will be
copied into the tag MCMR.DATA.READDATA[20] because 16320
represents a bit address within the memory of the MVI56E-MCMR
module (16320 / 16 = register 1020).
Reads 160 consecutive bits from the Slave device.
Issues the Modbus command to Modbus Slave Device Address 1.
Issues Modbus Function Code 1 to Read Coils.
MB Address in Device =
320
Function Code 1, MB Address in Device of 320 will read address
0321
Along with a count of 160, this command reads 0321 to 0480.
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