I am using the demo version of codesys ARM SL and testing the modbus RTU. I encountered the error where the package on the bus is correct, but codesys returns CRC FAIL.
I am using baud rate 115200, no parity, 8 data bits, 2 stop bits.
The signal in the attached image is a response to reading input registers (function code 4), length 2. The address of the slave is 0x07.
I calculated the CRC and it is correct, also shown in the attached image.
I am aware that the slave devices' response has a bit inserted after the function code, but it is like a third stop bit, and the start bit of the next byte has not occurred yet.
This bit does not cause any problems in communication with our other systems.
Hello,
I am using the demo version of codesys ARM SL and testing the modbus RTU. I encountered the error where the package on the bus is correct, but codesys returns CRC FAIL.
I am using baud rate 115200, no parity, 8 data bits, 2 stop bits.
The signal in the attached image is a response to reading input registers (function code 4), length 2. The address of the slave is 0x07.
I calculated the CRC and it is correct, also shown in the attached image.
I am aware that the slave devices' response has a bit inserted after the function code, but it is like a third stop bit, and the start bit of the next byte has not occurred yet.
This bit does not cause any problems in communication with our other systems.
Any ideas what is causing this problem?
Did you resolve it?