# Send Modbus custom request with TCP Socket **URL:** \ **Category:** Ignition\ **Tags:** perspective\ **Created:** [December 13, 2024, 9:28am UTC](https://forum.inductiveautomation.com/t/send-modbus-custom-request-with-tcp-socket/99788 "2024-12-13T09:28:04Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![David\_Gomez\_Alarcon](https://avatars.discourse-cdn.com/v4/letter/d/7ea924/32.png) [@David\_Gomez\_Alarcon](https://forum.inductiveautomation.com/u/David_Gomez_Alarcon)\ **Post date:** [December 13, 2024, 9:28am UTC](https://forum.inductiveautomation.com/t/send-modbus-custom-request-with-tcp-socket/99788/1 "2024-12-13T09:28:04Z")
Hello, I have a solar inverter that have a custom protocol (VABUS of Bonfiglioli) and I need to send a custom request for read de power of the inverter with bytes in TCP. I don't want testing with a real inverter so i'm using ModRSIM that is a Modbus TCP Server simulator and i want to read a holding register with a script for test how send bytes to a TCP Server. In python i have a script that works fine: ```python *import socket* *import time* *def trama_modbus():* * asdu = bytearray()* *#2 bytes para el transaction id* * asdu.append(0x00)* * asdu.append(0x01)* *#protocolo id, como es modbus esto es 00* * asdu.append(0x00)* * asdu.append(0x00)* *#va tener una longitud de 6 registros* * asdu.append(0x00)* * asdu.append(0x06)* *#el slave id es el 1* * asdu.append(0x01)* *#como vamos a leer holding es la fc 3* * asdu.append(0x03)* *#el primer registro a leer es el 3* * asdu.append(0x00)* * asdu.append(0x03)* *#el numero de registros que se pide en bloque es 1* * asdu.append(0x00)* * asdu.append(0x01)* * return asdu* *# Press the green button in the gutter to run the script.* *if __name__ == ' __main__':* * HOST = '127.0.0.1' # IP del servidor* * PORT = 507 # Puerto de escucha del servidor* * data = trama_modbus()* * print(data)* * s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)* * s.connect((HOST, PORT))* * s.send(data)* * time.sleep(1)* * resultado = s.recv(1024)* * print(resultado.hex())* * s.close()* ``` But I want do this in Ignition and I don't know how do it: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/a/8a226c8355baf357ceb505f7042b686710bf3614.png) I think that the problem is the creation of the message but i don't know how create the message. I'm using Ignition perspective but im testing this in Script Console of designer. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [December 13, 2024, 1:17pm UTC](https://forum.inductiveautomation.com/t/send-modbus-custom-request-with-tcp-socket/99788/2 "2024-12-13T13:17:51Z")
What doesn't work with your Ignition script? ---
**Author:** ![David\_Gomez\_Alarcon](https://avatars.discourse-cdn.com/v4/letter/d/7ea924/32.png) [@David\_Gomez\_Alarcon](https://forum.inductiveautomation.com/u/David_Gomez_Alarcon)\ **Post date:** [December 16, 2024, 8:42am UTC](https://forum.inductiveautomation.com/t/send-modbus-custom-request-with-tcp-socket/99788/3 "2024-12-16T08:42:43Z")
Sorry, I thought it wasn't working but I tried to write a value with FC = 6 and it works correctly, the problem is that I can't print the result correctly, which comes in ASCII characters. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/6/9688951880f20bc4724c2562d1cc74d1c982d9ef.png) I know that is ascii characters but i dont know how to print the result, in python i can print with print(resultado.hex()) but here in ignition i don't know ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [December 16, 2024, 8:44am UTC](https://forum.inductiveautomation.com/t/send-modbus-custom-request-with-tcp-socket/99788/4 "2024-12-16T08:44:41Z")
Please see [Wiki - how to post code on this forum](https://forum.inductiveautomation.com/t/wiki-how-to-post-code-on-this-forum/77831). ---
**Author:** ![David\_Gomez\_Alarcon](https://avatars.discourse-cdn.com/v4/letter/d/7ea924/32.png) [@David\_Gomez\_Alarcon](https://forum.inductiveautomation.com/u/David_Gomez_Alarcon)\ **Post date:** [December 16, 2024, 9:02am UTC](https://forum.inductiveautomation.com/t/send-modbus-custom-request-with-tcp-socket/99788/5 "2024-12-16T09:02:20Z")
Sorry,I put it in an image so that the result of the script could be seen. this is the code: ```python import socket import time def trama_modbus(): asdu = bytearray() #2 bytes para el transaction id asdu.append(0x00) asdu.append(0x01) #protocolo id, como es modbus esto es 00 asdu.append(0x00) asdu.append(0x00) #va tener una longitud de 6 registros asdu.append(0x00) asdu.append(0x06) #el slave id es el 1 asdu.append(0x01) #como vamos a leer holding es la fc 3 asdu.append(0x03) #el primer registro a leer es el 3 asdu.append(0x00) asdu.append(0x03) #el numero de registros que se pide en bloque es 1 asdu.append(0x00) asdu.append(0x01) return asdu # Press the green button in the gutter to run the script. if __name__ == ' __main__': HOST = '127.0.0.1' # IP del servidor PORT = 507 # Puerto de escucha del servidor data = trama_modbus() s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((HOST, PORT)) s.send(data) time.sleep(1) resultado = s.recv(1024) for i in resultado: print(i) s.close() ``` ---
**Author:** ![David\_Gomez\_Alarcon](https://avatars.discourse-cdn.com/v4/letter/d/7ea924/32.png) [@David\_Gomez\_Alarcon](https://forum.inductiveautomation.com/u/David_Gomez_Alarcon)\ **Post date:** [December 16, 2024, 11:29am UTC](https://forum.inductiveautomation.com/t/send-modbus-custom-request-with-tcp-socket/99788/6 "2024-12-16T11:29:01Z")
Problem solved, I use ord(i) in the loop and works. Thanks!