Not getting expected responses from motor according to ST manual. @Enrico Poli maybe you know
Is there something wrong with our Modbus packets or is what we are seeing correct and the manual is wrong?
The answers here seem OFF TOPIC and cause confusion. Solved: Re: EVALKIT-ROBOT-1 / MODBUS RTU / QUESTION - STMicroelectronics Community
We are told this from Manual UM2653: Getting started with the EVALKIT-ROBOT-1 - User manual
IF we concentrate on these steps one at a time – we should be good! Right ?
So step 1 wants us to make sure bit 1 here is set using the information at section 4.3.1!
4.3.1
Powering up the device seems successful with the device shaft moving to a position and HOLDING the shaft at that INDEX position.
We send the following MODBUS packet bytes at 19200
01 (slave address)
02 (MODBUS FUNCTION CODE to READ DISCRETE IN)
00 (MODBUS START ADDRESS MSB)
00 (MODBUS START ADDRESS LSB)
00 (NUMBER OF REGISTERS TO READ MSB)
01 (NUMBER OF REGISTERS TO READ LSB)
B9 (CRC)
CA (CRC)
Motor kit sends back
01 (slave address)
02 (MODBUS FUNCTION CODE to READ DISCRETE IN)
01 (MODBUS NUMBER OF BYTES TO FOLLOW)
00 (MODBUS DISCRETE INPUT VALUE) ????????????? BIT NOT SHOWING as SET “1”
A1 (CRC)
88 (CRC)
We send the following MODBUS packet bytes at 19200
01 (slave address)
02 (MODBUS FUNCTION CODE to READ DISCRETE IN)
00 (MODBUS START ADDRESS MSB)
00 (MODBUS START ADDRESS LSB)
00 (NUMBER OF REGISTERS TO READ MSB)
02 (NUMBER OF REGISTERS TO READ LSB)
B9 (CRC)
CA (CRC)
Motor kit sends back
01 (slave address)
02 (MODBUS FUNCTION CODE to READ DISCRETE IN)
01 (MODBUS NUMBER OF BYTES TO FOLLOW)
02 (MODBUS DISCRETE INPUT VALUE) ???????? (ALIGN BIT SET but DONE BIT CLEARED)
20 (CRC)
49 (CRC)
