Operating instructions

WirelessHART Fieldgate SWG70 10 Engineering
Endress+Hauser 63
10.2 Modbus Mapping
10.2.1 Modbus Settings
Modbus Settings determines how the Modbus information is to be transmitted by Fieldgate
SWG70 and where the information is to be found. It also allows the selection of automatic or
manual mapping. The set-up of the Modbus communication parameters (address, baudrate etc.) is
described in Chapter 8.3.4.
More details on the Modbus Interface itself and the way in which the HART parameters are mapped
to the Modbus registers is to be found in Appendix A.
1 Click on the Engineering =>Modbus Mapping =>Modbus Settings leaf to display the
associated parameters:
– The significance of the parameters is described in the table below
Modbus Settings
parameters
Parameter Meaning Example Default
Swap Option Selects frame format swap option for Modbus data transmission
(see also Appendix A.1.3)
• Big Endian: no swap
Register 0 Register 1
Source bytes: [0xABCD] [ 0xEFGH]
Target bytes: [0xABCD] [ 0xEFGH]
• Little Endian: Register swap;
Register 0 Register 1
Source bytes: [0xABCD] [ 0xEFGH]
Target bytes: [0xEFGH] [ 0xABCD]
The Swap Option does not apply to the Input Status registers
Big Endian Big Endian
Addressing Method Selects whether the mapping is to be done automatically or
manually
• Auto: Mapping is done automatically according to the rules
described in Appendix A.2
– There is no automatic mapping of Input Status
– The dialogues Input Status and Input Registers are deactivated
• Manual: Mapping is done manually or semi-automatically in the
Input Status and/or Input Register dialogues
Manual Auto
Read Modbus Registers
Mode
Determines in which registers the mapping is to be done
• Input Registers only: Values mapped to Input Registers
300001...365536
• Input and Holding: Values mapped to Input Registers
300001...365536 and Holding Registers 400001...465536
Inactive Inactive