Can't read value from register

[Song-H-J]

Hello, rasheeddo!

I ran the test_speed_control example.
The motor rotated successfully.
But the bellow error msg appears, and the rpm value could not be read from the register.

Set speed rpm control
'ModbusIOException' object has no attribute 'registers'
'ModbusIOException' object has no attribute 'registers'
'ModbusIOException' object has no attribute 'registers'
'ModbusIOException' object has no attribute 'registers'
'ModbusIOException' object has no attribute 'registers'
'ModbusIOException' object has no attribute 'registers'

How can I read the value normally?