VIM Modbus TCP/IP configuration data

Table: Device Data Type mapped to Device Register
Device Data Type	Device Register
0	COILS
1	INPUT STATUS
2	INPUT REGISTERS
3	HOLDING REGISTERS
6	VIM STATISTICS
All other values	Reserved

The Data start address specifies where in the PLC to read the data. This can be any PLC specific address. The following table describes examples of PLC registers and corresponding start addresses in the dataset.

Table: Example Data start address mapping
PLC Address	Start Address	Description
1	0	First coil in the PLC
501	500	PLC coil number 501
400001	0	First holding register
400950	949	Only the offset for the register is specified

For example, If the starting address is 0, the data type is 3 (Holding Registers) and the maximum number of values is 50, the DeltaV registers would be as shown in the table.

Table: Holding Register example
DeltaV Register	PLC or External Device Registers
R1	0 1
R2	2 3
R3	4 5
...	...
R50	99 100

Each dataset has a maximum of 100 16-bit values of DeltaV data type. Each DeltaV value is mapped to one or more PLC registers. If two registers are required, as is the case for floating point values, the registers must be consecutive. The following table describes the mapping.

Table: DeltaV data type mapping to PLC registers required
DeltaV Data Type	PLC Register Type	PLC Registers Required	Max Number of Values
Boolean	Coils Input Status	1 Bit	100
Discrete	Coils Input Status	1 Bit	100
Signed 8 bit Integer	Coils Input Status	1 Bit or Byte	100
Signed 16 bit Integer	Coils Input Status Input Registers Holding Registers	1 16-bit word	100
Signed 32 bit Integer	Holding Registers	2 16-bit words	50
Unsigned 8 bit Integer	Coils Input Status	1 16-bit word	100
Unsigned 16 bit Integer	Coils Input Status Input Registers Holding Registers	1 16-bit word	100
Unsigned 32 bit Integer	Holding Registers	2 16-bit word	50
Floating Point	Holding Registers	2 16-bit word	50
String	Holding Registers	1 byte	100

Table: Special data registers
Special data	Value and description
1	0 — Default is no customization. Floating Point and 32-bit data is represented as received. The transmitted byte order is 230, 102, 66, 246 1 — The transmitted byte order is 66, 246, 230, 102 2 — The transmitted byte order is 246, 66, 102, 230 3 — The transmitted byte order is 102, 230, 246, 66
2	0 — Default setting where 2 Modbus 16-bit registers are equivalent to 1 Floating Point or 32-bit value in DeltaV. There is a 1-2 correspondence between DeltaV value and read values. 1 — Data is not read as 2 MODBUS 16-bit registers but as individual Floating Point or 32-bit values. There is a 1-1 correspondence between DeltaV value and read value.
3	This is a delay parameter specified in 5ms units. When specified, it overrides the port Transmit delay for this dataset. The driver will delay for this amount of time before reading/writing the dataset.
4	This is a delay parameter specified in 5ms units. It applies only to datasets configured as Output, and Output mode 0 (block output). When specified, it provides a cyclic write of current dataset values from the VIM database to external devices. Note that normal functionality is for the VIM to write output data only when a change of state is detected.
5	Not Used