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Slave Address

Enter the Modbus slave address that will respond on this slave channel
The Slave Address must be a valid Modbus address (1 to 255), and must be unique for all Slave Attach Lists on this Slave Channel. 

ReservedReserved field, currently unused. 
Source ChannelMaster Channel or Internal Channel of the Field Unit and RTDB to be attached to this Slave unit. 
Source Field Unit

Field Unit address containing the RTDB to be used as data represented in this Slave unit. 

32-bit data is only supported in 40,xxx RTDB registers, not 30,xxx registers. In order for the Modbus Slave Attach to work properly, the registers in the attached RTDB must be defined in a specific order. That order is: 

  • Booleans (should be addresses in the ranges of 1-9999 and 10,001-19,999)
  • There should be no registers defined in the range of 20,000-30,000. 
  • 16-bit registers (should be addresses in the ranges of 30,001-39,999 or 40,001-49,999; there must also be at least one 16-bit holding register defined at the beginning of the 40,xxx range, before any 32-bit types)
  • UINT32
  • or SINT32 registers (should be addresses in the 40,xxx range,
above the
  •  numbered greater than the 16-bit registers)
  • REAL32 registers (floating point registers should be addresses in the 40,xxx range,
above the
  •  numbered greater than the UINT32 registers) 
  • String registers are not fully supported in the Modbus Slave.

NOTE: The RTDB attached to the Modbus slave should include at least one register in each of the four address ranges (1, 10001, 30001, 40001), observing the rules stated in the bullets above. For instance, if the RTDB definition includes 16-bit registers after UINT32 or


REAL32 registers, those 16-bit registers will not work properly when attached to the Modbus Slave.

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Network Slave Channel (SlaveNetwork, SlaveModbusTCP)