Comtrol IO-Link Master EIP-4 - Manual (Page 27)

IO-Link Master EtherNet/IP Reference Manual: 2000589 Rev. A Chapter 2. Functionality Descriptions - 27
ISDU Response Message Format
2.2.3. ISDU Response Message Format
The ISDU responses have the same data format as requests with the only exception being the returned
command status. Each ISDU response message is comprised of one or more responses to the single and/or
nested command(s) received in the request.
2.2.3.1. Standard ISDU Response Command Format
The following table show the standard ISDU response command format with ControlLogix PLCs.
Name Data Type Parameter Description
Status USINT
Indicates the byte alignment and status of the command response.
Byte swapping, bits 0-3:
0= No byte swapping.
1= 16-bit (INT) byte swapping of TX/RX ISDU data.
2= 32-bit (DINT) byte swapping of TX/RX ISDU data.
Status, bits 4-7:
0 = NOP (No operation)
1 = In process (Only valid for non-blocking requests)
2 = Success
3 = Failure: IO-Link device rejected the request.
4 = Timed out: IO-Link device did not respond
RdWrControlType USINT
Provides the control and type of ISDU request
Bits 0-3, Type Field:
0 = NOP (No operation)
1 = Read operation
2 = Write operation
3 = Read/Write “OR”
4 = Read/Write “AND”
Bits 4-7, Control Field:
0 = Single/Last Operation (length can vary from to 1 to 232)
1 = Nested batch command – fixed 4 byte data area
2 = Nested batch command – fixed 8 byte data area
3 = Nested batch command – fixed 16 byte data area
4 = Nested batch command – fixed 32 byte data area
5 = Nested batch command – fixed 64 byte data area
6 = Nested batch command – fixed 128 byte data area
7 = Nested batch command – fixed 232 byte data area
Index UINT The parameter address of the data object in the IO-Link device.
Subindex UINT
The data element address of a structured parameter of the data
object in the IO-Link device.
Datalength UINT
Length of data that was read or written.
For nested batch commands, the data length can vary from 1 to
fixed data area size.
Data
Array of
USINTs,
UINTs, or
UDINTs.
Data required for read commands. Optionally can return the data
of a write command.
The size of the array is determined by the Control field in the
RdWrControlType.
Note: Data field not required for single NOP commands.