Moxa Technologies NE-4100 user manual DIO Commands, Command Packet Format Length Bytes Header Data

C

DIO Commands

In this appendix, we give the reference DIO commands used to access the Digital I/O status of the Network Enabler from an Ethernet network. The Digital I/O status can be accessed by a specific TCP port (default 5001) on the Network Enabler.

Command Packet Format:

Length (Bytes)	4	1 – 255
Format	*Header	Data

Send the Command packet to the Network Enabler. “Data” field is command specific.

ACK Packet Format:

Length (Bytes)	4	1 -255
Format	*Header	Data

The Network Enabler returns by ACK packet. You can get the Digital I/O status and input/output operation mode by checking the “Data” field of the packet.

*Header Format:

Length (Bytes)	1	1	1	1
Format	Command	Version	Command Status	Length (for data)
		(must be 2)

Check the “Command Status” to get the result after sending the Command packet.

Command: This field defines the command code. For example, 1(hex) represents “read single D I/O.” For more information, please refer to following content.

Command Status: This field returns the status of the command. 0 – OK

1 – Command error; may be unknown

2 – Version error; not supported by this version

3 – Length error; the length member does not match the attached data

4 – Operation error; you cannot set the DIO mode to input mode, and set the DO status at the same time

5 – “Packet too short” error

6 – DIO number error; might not support request DIO number 0xFF – other unknown error

Data Structure Definition:

C code example:

//define DIO Header format

typedef struct _DIO_Header_Struct {

char	command;
char	version; /* This specification is version 2 */
char	status;
char	length;

} DIOHeaderStruct, *pDIOHeaderStruct;