This is read from my PIC MCU. Modbus Poll using reads for testing. The 7th device is read well by adjusting the delay time in Modbus Poll. MCU Serial _ 3 : connect Device #6 ~ #12 (Digital Input(40001) 4 ea, Digital Output(40001) 2 ea, Analog Input(40001, 40002) 1 ea)(RS-485) Modbus Address : DI 400...

Thanks for your help. 1 second flash confirmed. Timer interrupts are working normally Slave addresses do not overlap. Testing every slave individually results in very slow reads. Two slaves cannot be read. If I read it with another computer program (Modbus Poll), a Time Out error occurs at the 7th D...

Multiple networks must be operated on one MCU.
In fact, even if only one address is accessed from one device in one master, the MCU becomes very slow and data cannot be accessed. I asked other programmers, but they said this never happened.

Thank you for your interest.

Here my project.

Thank you.

That is different serial port
MCU have 6 serial port

I am using Modbus master. MCU : PIC24FJ512GA606 Device : Serial_1 : Modbus RTU via RS-485(7ea)(Master) Device : Serial_2 : Modbus RTU via RS-485(5ea)(Master) HMI : Serial_3 : Modbus RTU via RS-232(1ea)(Slave) There are 7 devices. One address 40001 is loaded in Modbus RTU mode for each device. The de...

Hello?
I program using the 3XXXX Holding Register address.
This advantage is that only one address is used during Modbus communication and there is less error occurrence.

Hope this helps.

I tried changing the SPI Prescale. But the clock rate doesn't change and the error still occurs. 10Hz is generated by the MCU, and when viewed with an oscilloscope, it is measured as approximately 9.96Hz. And if you change the hardware channel, the system won't work (maybe hangup?) Also, if I2C is c...

Is there any way I can do it?
I'm sorry to have been troublesome.

Modbus Poll accured read error, Write Error, Response Error, and Exception Error 31. 97. 32

Ping is OK.

And SPI operates only in Software Mode.