我遇到了最小modbus 库的问题。从机没有响应主机的请求，我要请求读取。我正在使用带有 Python 3.10.1 的 Raspberry Pi 3 Model B+，它是 2.0 版的最小modbus 库。我使用 Arduino Mega 作为从机，我还使用 Mini Adapter Serial Converter USB to RS485 是用于 Arduino 的转换器模块 RS485。
import serial
import minimalmodbus
instrument = minimalmodbus.Instrument('COM6',1)
instrument.serial.baudrate = 9600
instrument.serial.timeout = 10
instrument.clear_buffers_before_each_transaction = True
instrument.debug = True
temperature = instrument.read_register(1,1)
print(temperature)
MinimalModbus debug mode. Will write to instrument (expecting 7 bytes back): 01 03 00 01 00 01 D5 CA (8 bytes)
MinimalModbus debug mode. Clearing serial buffers for port COM6
MinimalModbus debug mode. No sleep required before write. Time since previous read: 87898406.00 ms, minimum silent period: 4.01 ms.
MinimalModbus debug mode. Response from instrument: (0 bytes), roundtrip time:10.0 ms. Timeout for reading: 0 ms.