How to send Acknowledgement to device

[Ptwtech]

Hello ,
I want to send acknowledgement to device in hex format.
I'm doing this.please help me how to send acknowledgement in hex format
Thanks

var data;
if(msg.payload.length == 17){
data= stringToHex('01');
}else{
data= stringToHex('00','utf8');
}
msg.payload = data;
return msg;

[zenofmud]

Add a catch node connected to a debug node (set to display the complete msg object) and see if that will lead you to figuring out your issue.

also, if you just want to send back a hex 0 or 1 why not to that? For reference take look at https://www.w3schools.com/js/js_numbers.asp The section on Hexadecimal

[Ptwtech]

I want to send acknowledgement like this i.e 1 byte 0x01 or 0x00.

[zenofmud]

if you just want to send back a hex 0 or 1 why not to that? For reference take look at https://www.w3schools.com/js/js_numbers.asp The section on Hexadecimal

[Steve-Mcl]

there is no such function stringToHex unless you make it.

hexadecimal 0x0 is simply 0 and hex 0x01 is simply 1.

If you want to send a hex string then just set payload to "00" or "01"

[Ptwtech]

Actually, i also did this msg.payload =0x01; & msg.payload =0x00; in this scenario device getting 30 or 31

if(msg.payload.length == 17){
msg.payload =0x01;
}else{
msg.payload =0x00;
}
return msg;

And also did this msg.payload ='01'; & msg.payload ='00'; in this scenario device getting D3.

if(msg.payload.length == 17){
msg.payload ='01';
}else{
msg.payload ='00';
}
return msg;

Device Should be received 01 or 00.

[Steve-Mcl]

@Ptwtech

Actually, i also did this msg.payload =0x01; & msg.payload =0x00; in this scenario device getting 30 or 31

30 is ASCII '0' and 31 is ASCII '1' - something in the transmission path is converting the number in payload to a character before or during transmission.

I realise now you are trying to transmit NUL and STX - which are not really idea characters to send as ACK or NAK.

Can you share your flow so we can see if there is something is possible.

Alternatively, can you change the code in the other device to accept a string/ASCII response like "OK" or "NG"?

[Ptwtech]

i want to send acknowledgement to device ...should be sent as binary packet. I.e. 1 byte 0x01 or 0x00.

Thansks

[Steve-Mcl]

You need to share your flow - I cannot see how you have set the nodes from a screenshot.

Also, some questions...

• What is the End device?
• is it possible to change the end device to use something else (like a string or a different protocol)?