hello all, i am implementing modbus protocol for HMI touch screen display with LPC2148. i have written my code and it is working fine. i am facing problem is function code of 0x10. i get query and i response. upto this it is fine but after responding HMI again gives me 01 00 00 DF (DF can be any 8bit number but 01 00 00 is constant). pls explain me what it is. thank you reagards
MODBUS implementations are typically very different from one another, and to make things even worse - you provided no details whatsoever! It's like saying: "My car does not start. What is wrong?" while refusing to go to a garage...
hello sir thanks for for reply. i am using modbus RTU 984 format and i followed the pdf of it and wrote the code. now i am facing problem in 0x10 function code. after replying HMI again sends 0x01 0x00 0x00 0xdf. which is this string. this protocol supports 0x10 function code but still i have the problem. i am using rs-422 communication and it is working fine as my other code for function code is working well. any information do you require? thank you regards
Start anew: what is the problem? slowly and clearly - what does not work?
What is this "HMI" that you keep on about?
Is it something that you've written yourself, or is it from some 3rd party?
If it's something that you've written yourself, then it's obviously up to you to debug what you have written!
If it's from some 3rd party, then you should contact them for support - maybe they intended it to work that way...?