This post I will show you how to use Beckhoff TwinCAT3 TF6340 to serial Communicate with micro:bit. Why I chose Micro:bit – It is a very good device that has a 3-axis acceleration sensor, temperature sensor,etc. And the price is only 3000 yen.

System Requirment

Install

Please access the following link to download the exe files.

https://www.beckhoff.com/en-en/products/automation/twincat/tfxxxx-twincat-3-functions/tf6xxx-tc3-connectivity/tf6340.html

Choose English and OK.

Please wait a second..

Click Next>.

Accept the license and Press Next>.

Enter the username and Organization, then press Next>.

Choose Complete as your setup type and Press Next>.

Next>.

Install.

Please wait a second.

The installation is Finished.

Configuration

Reference to the Manual , there are 3 types of configuration of TF6340.

Option 1: PC COM ports
- Connect COM Port directly to PLC.
Option 2: Beckhoff terminals
- Connect the Devices to Beckhoff Field bus terminal (Max 100m)
  - KL6xxx Bus Terminals
  - EL60xx EtherCAT Terminals
Option 3:Virtual COM port
- We will use this Option and make sure the usb that you connected , COM1..COMM255 is detected in your window system.

Support Hardware

まず最大の有効データ転送レート(bps)以下の要素に左右されます。

PLC Cycle Time
Total Bit that you need
- 1 Start bit
- N Data bits
- P parity bits
- m Stop bits
- Total:Start bit+n Data bit+ P Parity bits +m stop bit

I tried Option Serial PC interface and Virtual serial COM port and will explain these two options.

Serial PC Interface

The PC interface(COM1…COM255) is managed by the TwinCAT system.64 bytes buffer is used inside the Library – the max data exchange is 64 bytes in one time. And then the the system needs 3 cycles to exchange the data.

Bps=(LB*64/3)/T.

Virtual serial COM port

If we are using Virtual serial Com port(COM1..COM255), we do not need to configure anything in the TwinCAT system Manager.All the communication parameters are configured in the user program.

But this type of connection is not a Real-time communication.

The baud rate that you can set is from 150 to 128000.

Function Block

Sorry that I will only explain the Function Blocks that I am using in the example.

SerialLineControlADS

you need to cyclic call this block in the PLC and this block will manage the communication between PLC and Virtual serial interface.

If Connect is True, Runtime will refer to the SerialCfg setting and start to connect to the device.you need to change the status to false and true again while the SerialCfg setting is changed.All the stuff of port open,close is managed by Function block.

VAR_INPUT
Connect	Bool	True=Open the Port False=Close the Port
SerialCfg	ComSerialConfig	Serial Port setting
NetId	T_AmsNetId	Keep empty while you access local.
Timeout	TIME	Default=5s
VAR_IN_OUT
TxBuffer	ComBuffer	Buffer of Data Transfer Function Block of SendByte,SendData, SendString will use this.
RxBuffer	ComBuffer	Buffer of Data ReceivedFunction Block ofReceiveByte, ReceiveData, ReceiveString will use this.
VAR_OUTPUT
PortOpened	BOOL	True=Port is opned
Error	BOOL	True=Error is occured
ErrorID	UDINT
Busy	BOOL	True=ADS is communicating
TxBufCount	UDINT	data that TxBuffer is still not sent
RxBufCount	UDINT	data that RxBuffer is still not received

ComSerialConfig

Basically the key setting is ComPort,Baudrate,Parity,DataBits.

ComPort	UDINT	1-255
Baudrate	UDINT
Parity	ComParity_t
DataBits	INT
DTR	ComDTRCtrl_t
RTS	ComRTSCtrl_t
CST	BOOL
DSR	BOOL
TraceLevel	BYTE	None=0;Error=1,Warning=2,Info=3,Verbose=4,Noise=5
Reserved1	BYTE
Reserved2	BYTE
Reserved3	BYTE

ComBuffer

Do not directly modify the value of this variable.You only need is – define this variable and pass it as TxBuffer and RxBuffer parameters in SerialLIneControlAds.

Buffer	ARRAY[0..300] OF BYTE
RdIdx	INT
WrIdx	INT
Count	INT
FreeByte	INT
Error	INT
blocked	BOOL

ReceiveString

This is the Function Block to receive the data from serial communication as String format.

VAR_INPUT
Prefix	STRING	if not empty, the starting characters must match with this.
Suffix	STRING	if not empty, the Ending characters must match with this.。
Timeout	TIME
Reset	BOOL
VAR_IN_OUT
ReceivedString	STRING	Default=5s
RxBuffer	ComBuffer	Buffer of Data ReceivedFunction Block ofReceiveByte, ReceiveData, ReceiveString will use this.
VAR_OUTPUT
StringReceived	BOOL	True=String is Received
Busy	BOOL	True=Executing
Error	ComError_t	Error ID
RxTimeout	BOOL	True=Timeout

micro:bit

Let’s take a serial communication test between your PC and micro:bit.

please click the follow links below:

https://makecode.microbit.org/

Go to My Projects>New Project.

We can program in the Web browser and IDE installation is not necessary.

you can use High languages just like javascript or Python but Blocks is used in this time.

Here is the testing program.

It just creates a variables that called sMessage and join all the acceleration sensor values in String format, finally output to serial line.

Let’s click the “Show Console Simulator” to view the output.

0,0,-1023 is shown.

416=currently output Count

0,0,-1023 are the acceleration sensor output value.

Click the Download button to Download your code.

you can see the files with .hex on your PC.

Connect the micro:bit board with USB and drag the .hex files to micro:bit.

Test

Putty is used in this testing and it is a very good tool.

Please download the link below.

https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

Start up the Device Manager.

confirm the COM port of micro:bit.

Start the Putty.

Connection Type：Serial

Serial line ：COM3

Speed ：115200

You can enter the name of sessions if you want to save the configurations,then press the “save” button.Next time you just need to choose the session you saved and then press the ”load” button.

Finally,Press the “Open” button to open the terminal.

If you can see the data that comes from Micro:bit, the communication is successful.

Example

Here is the Configurations.

Mirco:bit Side

Same as below.

Program

References>Add library.

Search TC2_SerialCom and add it into your project.

VAR

VAR

RxBuffer :ComBuffer;
TxBuffer :ComBuffer;

SerialLineControlADS :SerialLineControlADS;
bConnect :BOOL;
stSerialCfg :ComSerialConfig;
sNetId :T_AmsNetId;
bAdsError :BOOL;
bReset :BOOL;
AdsErrorID :UDINT;

ReceiveString :ReceiveString;
data :STRING;
nReceiveCounter :UDINT;
END_VAR

PROGRAM

you can refer to the setting in putty to match the serial communication setting in the user program.

//Config
stSerialCfg.Baudrate:=115200;
stSerialCfg.ComPort:=3;
stSerialCfg.DataBits:=8;
stSerialCfg.StopBits:=1;
stSerialCfg.Parity:=PARITY_NONE;

//Reset
IF bReset THEN
bAdsError:=FALSE;
nReceiveCounter:=0;
END_IF

//Open command line
SerialLineControlADS(
Connect:=bConnect
,SerialCfg:=stSerialCfg
,NetId:=sNetId
,Timeout:=
,TxBuffer:=TxBuffer
,RxBuffer:=RxBuffer
);

//Error
IF SerialLineControlADS.Error THEN
bAdsError:=TRUE;
AdsErrorID:=SerialLineControlADS.ErrorID;

END_IF

//Receive data
ReceiveString(
Prefix:=’x:’
,Suffix:=’$R$N’
,Timeout:=
,Reset:=
,ReceivedString:=data
,RXbuffer:=RxBuffer
);

//Total Counter
IF ReceiveString.StringReceived THEN
nReceiveCounter:=nReceiveCounter+1;
END_IF

Result

You can see the data that sent from Micro:bit

Beckhoff twincat とmicro:bit と繋がりました〜3軸の加速センサーデータtwincat に送ります。ー記事はまた後ほどで❗️〜#beckhoff #twincat #plc #microbit pic.twitter.com/PXXkSknz7g
— 3threes (@3threes2) September 22, 2021