The PLC library Tc3_IoLink is a library that can be used for communication with IoLink devices, and it supports the following profiles:

Common Profile
Smart Sensor Profile

Within this library, there are function blocks available that allow for the reading and writing of parameters.

System requirements

WinXP, WES, Win7, WES7, WEC7 IPC or CX, (x86, x64, ARM)
Min. TwinCAT Version：3.1.4024.25
Min. TwinCAT Level：TC1200 TC3 PLC

Reference Link

Beckhoff#Let’s use EL6224

Basic

Before using Tc3_IOLINK, let me guide you on how to read data from an IO-LINK device using the Beckhoff TwinCAT’s AoE screen. Please click on EL6224.

Open the AoE-Online Tab.

You can select a Port number from the Port Drop-Down List in the IO-Link Profile.

This time, we sent a Read command to Port 4, Index 16, SubIndex 0.The string “Contrinex AG” is returned in the Read-String.

In fact, you can check the Index, SubIndex, Data Type and Default value of each Index by checking the IO-LINK Device Manual of each company.

How to check the AMS Net-ID?

Open EL6224 and from >AoE-Onlne ,there is a field called NetId.

This number is the AMS Net-ID.

Add library

Add Tc3_IoLink library by Reference>Add Library.

Search for Tc3_IoLink and add Library with Ok.

DUT

Here are the DUTs used in this article.

E_IolPort

Specifies the port number.

Port1	1
Port2	2
Port3	3
Port4	4
Port5	5
Port6	6
Port7	7
Port8	9

E_IolPortError

This is the error content of IO-Link communication.

NoError	0
WatchdogDetected	1
InternalError	2
InvalidDeviceID	3
InvalidVendorID	4
InvalidIOLinkVersion	5
InvalidFrameCapability	6
InvalidCycletime	7
InvalidPdInLength	8
InvalidPdOutLenght	9
NoDeviceDetected	10

E_IolPortState

This is the communication information of IO Link Port.

Disabled	0
stDigIn	1
stDigOut	2
CommunicationOP	3
CommunicationComstop	4

Function

Here are the Functions used in this article.

F_IolGetChannelStateTxt

This function converts the IO-LINK Port status into text format.

VAR_INPUT

Variables	Type	Description
nIolChState	USINT	IO-LINK channel status value
nPort	E_IolPort	Port number of the IO-LINK whose status you want to retrieve

VAR_OUTPUT

Variables	Type	Description
F_IolGetChannelStateTxt	String(255)	Convert channel status into text information.

F_IolGetPortError

This function returns the error status of the IO-Link Port.

VAR_INPUT

Variables	Type	Description
nIolChState	USINT	IO-LINK channel status value

VAR_OUTPUT

Variables	Type	Description
F_IolGetPortError	E_IolPortError	Indicates IO Link Port error information

F_IolGetPortState

This function returns the status of the IO-Link Port.

VAR_INPUT

Variables	Type	Description
nIolChState	USINT	IO-LINK channel status value

VAR_OUPUT

Variables	Type	Description
E_IoLGetPortState	E_IolPortState	Indicates Port status

Function Block

Here is the Function Block used in this article.

FB_IolRead

This Function Block reads the parameters of the IO-link device.

VAR_INPUT

Variable	Type	Description
bExecute	BOOL	Run at startup
sNetid	T-AmsNetid	IO Link Master’s AMS NET-ID
nlolPort	E_lolPort	IO-Link Port number you wish to access
nIndex	WORD	Index of the IO-Link device you want to access
nSubindex	BYTE	SubIndex of the IO-Link device you want to access
pDSTBuf	PVOID	Memory Offset where data read from the IoLink device is stored.
cbBufLen	UDINT	Total Size of the storage location for data read from the IoLink device
tTimeout	TIME	Maximum execution time

VAR_OUTPUT

Variable	Type	Description
bBusy	BOOL	True=Executing
bDone	BOOL	True=Execution succeeded
bError	BOOL	True=Error exists
hResult	HRESULT	Return value of Function Block
nADSError	E_AdsErr	ADS Error Code
nIolError	E_IolError	IO-Link error code

FB_IolWrite

This Function Block writes the parameters of the IO-link device.

VAR_INPUT

Variable	Type	Description
bExecute	BOOL	Run at startup
sNetid	T-AmsNetid	IO Link Master’s AMS NET-ID
nlolPort	E_lolPort	IO-Link Port number you wish to access
nIndex	WORD	Index of the IO-Link device you want to access
nSubindex	BYTE	SubIndex of the IO-Link device you want to access
pSRCBuf	PVOID	Memory Offset of the destination for data to be written to the IoLink device.
cbBufLen	UDINT	Total Size of the destination for data to be written to the IoLink device
tTimeout	TIME	Maximum execution time

VAR_OUTPUT

Variable	Type	Description
bBusy	BOOL	True=Executing
bDone	BOOL	True=Execution succeeded
bError	BOOL	True=Error exists
hResult	HRESULT	Return value of Function Block
nADSError	E_AdsErr	ADS Error Code
nIolError	E_IolError	IO-Link error code

Implementation1-F_IolGetChannelStateTxt

F_IolGetChannelStateTxt Function is used to take the current Port state.

Program

The StateCh4 variable should actually be linked to the State variable of the EL6224.

VAR
StateCh4 AT %I*:USINT;
nPort :E_IolPort:=E_IolPort.Port4;
sChannelStateTxt :STRING;
END_VAR

//F_IolGetChannelStateTxt
sChannelStateTxt:=F_IolGetChannelStateTxt(
nIolChState:=StateCh4
,nPort:=nPort
);

Result

When the IOLINK device is communicating normally, the text “Port4 is state CommunicationOP ” will return.

However, when I unplug the cable that is connected to the IO LINK device, the text changes to “Port 4 is state Disabled and has error NoDevice Detected”.

Implementation2-F_IolGetPortError

F_IolGetPortError Function is used to take the error status of the current Port.

Program

The StateCh4 variable should actually be linked to the State variable of the EL6224.

VAR
StateCh4 AT %I*:USINT;
sPortError :E_IolPortError

END_VAR

//F_IolGetPortError
sPortError:=F_IolGetPortError(
nIolChState:=StateCh4
);

Result

NoErrorOP’ returns when the IO LINK device is communicating normally.

However, when I unplug the cable connected to the IO LINK device, it changes to “NoDevice”.

Implementation3-F_IolGetPortState

F_IolGetPortState Function is used to take the current Port state.

Program

The StateCh4 variable should actually be linked to the State variable of the EL6224.

VAR
StateCh4 AT %I*:USINT;
sPortState :STRING;
END_VAR

//F_IolGetPortState
sPortState:=F_IolGetPortState(
nIolChState:=StateCh4
);

Result

When the IO LINK device is communicating normally, “CommunicationOP” will return.

However, when I disconnect the cable connected to the IO LINK device, it changes to “Disabled”.

Implementation4-FB_IolRead

We will use FB_IolRead Function Block to read the status of Index 16#10 and SubIndex 16#0 of the IO LINK device currently connected to the Port.

Program

VAR

FB_IolRead :FB_IolRead;
DSBuffer :STRING(255);
nPort :E_IolPort:=E_IolPort.Port4;
FB_IolRead_Execute :BOOL;
END_VAR

//FB_IolRead

FB_IolRead.bExecute:=FB_IolRead_Execute;
FB_IolRead.sNetId:=’169.254.141.157.2.6′;
FB_IolRead.nIolPort:=nPort;
FB_IolRead.pDSTBuf:=ADR(DSBuffer);
FB_IolRead.cbBufLen:=SIZEOF(DSBuffer);
FB_IolRead.nIndex:=16#10;
FB_IolRead.nSubindex:=0;

FB_IolRead();

Result

Done!Contrinex returned.

Implementation5-FB_IolWrite

we will use FB_IolWrite Function Block to change the current value of Index 16#40 and SubIndex 16#3 of the IO LINK devices currently connected to the Port.

Program

VAR
FB_IolWrite:FB_IolWrite;
FB_IolWrite_Execute:BOOL;
SensorMode :USINT;
nPort :E_IolPort:=E_IolPort.Port4
END_VAR

SensorMode:=16#18;
SrcBuff:=’Beckhoff’;
FB_IolWrite.bExecute:=FB_IolWrite_Execute;
FB_IolWrite.sNetId:=’169.254.141.157.2.6′;
FB_IolWrite.nIolPort:=nPort;
FB_IolWrite.pSRCBuf:=ADR(SensorMode);
FB_IolWrite.cbBufLen:=sizeof(SensorMode);
FB_IolWrite.nIndex:=16#40;
FB_IolWrite.nSubindex:=3;

FB_IolWrite();