Sending hex from matlab to longer pump device

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Mathieu
Mathieu 2023-3-3
评论： Mathieu 2023-7-19
Hello everybody
First of all, I am a beginner in communication protocols
I recently started to try to control LongerPump BT1002J with matlab. I'm able to control it with a special software (pictures 1), everything works
I would like to use Matlab to be able to send the same thing to my device, but I think the format of the pin in not correct and the pump seems to not understand what I am sending to it.
I used the folowing code:
clear all
instrreset
s = serialport('COM6',1200);
fopen (s)
Str = 'E9 01 06 57 4A 00 0A 01 01 10';
D = sscanf(Str, '%2x');
fwrite(s, D, 'uint8')
I tried to remove blanks between E9 01 etc, but it is not effective. The line is sent ( I can see it with my RS485 converter, the led lights up.
Can anyone could correct the mistake in this code please?
Thank you for your help
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Walter Roberson
Walter Roberson 2023-3-7
Ran in:
Well, let us do a test:
Str = 'E9 1F 06 57 4A 00 0A 01 01 0E';
D = sscanf(Str, '%2x').'
D = 1×10
233 31 6 87 74 0 10 1 1 14
filename = tempname + ".txt";
%write process you are using now
fid = fopen(filename, 'w');
fwrite(fid, D, 'int8');
fclose(fid);
fid = fopen(filename, 'r');
stored = fread(fid, [1 inf], 'uint8');
fclose(fid);
disp(stored)
127 31 6 87 74 0 10 1 1 14
%write process with greater certainty
D2 = typecast(uint8(D), 'int8');
fid = fopen(filename, 'w');
fwrite(fid, D2, 'int8');
fclose(fid);
fid = fopen(filename, 'r');
stored = fread(fid, [1 inf], 'uint8');
fclose(fid);
disp(stored)
233 31 6 87 74 0 10 1 1 14
This suggests that your use of write() with 'int8' is equivalent to first doing int8(D) and writing the result -- which is not going to work because some of your values are greater than 127. The type specification you use in write() or fwrite() does not do a typecast() of the data, it does a cast() of the data
Mathieu
Mathieu 2023-3-21
编辑：Mathieu 2023-3-21
Hello Sir, first of all thank you very much for your answer and sorry for the slowness of mine
If I understand what you said, I need to use typecast() function in order to convert my str command ('E9 1F 06 57 4A 00 0A 01 01 0E') to HEX format because fwrite does not work as I thought. Then, I should send the converted command through my serial port?
EDIT:
I tried this one:
%% configuration and opening of the serial port
s = serialport('COM8',1200,'Parity','Even','DataBits',8,'StopBits',1); %open the serial port
fopen(s);
%% conversion step of the command format
Str = 'E9 1F 06 57 4A 00 0A 01 01 0E'; %command to be sent
D = sscanf(Str, '%2x').';
filename = tempname + ".txt";
fid = fopen(filename, 'w');
fwrite(fid, D, 'int8');
fclose(fid);
fid = fopen(filename, 'r');
stored = fread(fid, [1 inf], 'uint8');
fclose(fid);
disp(stored)
%% Here, the converted string command is sent to the seriaporl
fwrite(s, stored, 'int8')
display("the command has been sent")
clear all
But it does not work, because you said that fwrite was not compatible.. What should I replace the fwrite function with? I don't see how to use typecast function.

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采纳的回答

Daniele Sportillo
Daniele Sportillo 2023-3-21
移动：Walter Roberson 2023-3-30
Hi,
this should work
s = serialport('COM8',1200,'Parity','Even','DataBits',8,'StopBits',1); %open the serial port
Str = 'E9 1F 06 57 4A 00 0A 01 01 0E';
D = sscanf(Str, '%2x').';
write(s,D,"uint8");

更多回答（2 个）

JOUDI ARMOUCH
JOUDI ARMOUCH 2023-5-19
If its possible, can I know which software you used in picture 1?
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JOUDI ARMOUCH
JOUDI ARMOUCH 2023-6-15
Thank you for your answer and time, really appreciated..
I have a project related to this type of longerPump, if you do not mind can I have a way to communicate with you and ask some questions.
Mathieu
Mathieu 2023-6-15
Hello
I've added you on Linked In, we can chat there if you don't mind.

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Florian Mueller
Florian Mueller 2023-7-11
Dear Mathieu,
I also try to use a Longer pump ... and failed.
Would you mind sharing what software you used (and maybe you have a better user manual than I found).
Thanks a lot already!
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Florian Mueller
Florian Mueller 2023-7-18
Mathieu, THANK YOU.
Thanks to this thread and all the replies, I finally managed to get this to work ... Longer pumps are nice and cheap, but the documentation is not very clear.
Mathieu
Mathieu 2023-7-19
Great news! Yes, I agree, the documentation isn't clear, but I have to admit that the person I contacted at longer pump company was very helpful. Anyway, congratulations!

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