IEC-61131 Addressing

This topic describes the IEC addressing format as used in the RMC. For other addressing formats, see the Register Map Overview topic.

The RMC uses the IEC-61131 standard for its register addresses. This format can be used in User Programs and Expressions, although Delta recommends using tag names where possible.

Address Format

The IEC address format for the registers in the RMC is:

%MDfile.element

where

M indicates it is a location in memory.

D indicates it is a 32 bit word.

file = the file number. This file number corresponds to the file number in the DF1 addressing.

element = the element number. This element number corresponds to the element number in the DF1 addressing.

Example

For the RMC75, %MD8.8 is the Axis 0 Actual Position, and %MD8.0 is the Axis 0 Status.

Individual Bits

Some RMC registers contain individual bits that you may wish to address. The IEC address for a specific bit in the RMC is:

%MXfile.element.bit

where

M indicates it is a location in memory.

X indicates it is a single bit.

file = the file number.

element = the element number.

bit = the bit number (0-31).

Example

The user would like the address for the RMC75 Enable Output Status Bit on axis 0. Then,

file = 8, the file number for Axis 0 Status registers,

element = 0, the element number of the Status Bits register,

and

bit = 7, the bit number for the Enable Output bit.

Therefore, the address is %MX8.0.7

Discrete I/O

Discrete Inputs and Outputs can be addressed in IEC format as shown below. The IEC address is also displayed in the Discrete I/O Monitor and the Discrete I/O Configuration dialog.

RMC75

RMC150 and RMC200

%IXnumber or %QXnumber

where

I indicates it is an input.

Q indicates it is an output.

X indicates it is a single bit.

number = the I/O number.

%IXslot.number or %QXslot.number

where

I indicates it is an input.

Q indicates it is an output.

X indicates it is a single bit.

slot = the slot number of the RMC, starting with slot 0 to the left.

number = the input or output number.

Discrete I/O are also mapped to the Discrete I/O registers and can be addressed by addressing the bit in the register. See the RMC150 DI/O, RMC75 DI/O, and RMC200 DI/O register map topics for the addresses of the I/O.

Occasionally, an addresses may need to be represented in integer format. This section describes how to convert register addresses from the standard register representation to an integer.

RMC addresses are represented in IEC 61131 address format as:

%MDfile.element, where file = file number, and element = element number.

Use the following equation to convert a register address to integer format, N:

N = file * 4096 + element

Example