I have one energy meter and i am trying to retrieve voltage, freq values from meter on raspberry pi uart over RS485
My connections for raspberry pi and rs485 are as follows Rs485 DI - Tx of raspberry pi Rs485 R0 - Rx of raspberry pi Rs485 DE/RE -Pin 7 of raspberry pi
my code is as follows:
import serial import RPi.GPIO as GPIOfrom pymodbus.client.sync import ModbusSerialClient as ModbusClient
from pymodbus.register_read_message import ReadInputRegistersResponsefrom pymodbus.register_read_message import ReadInputRegistersRequest
import logging
logging.basicConfig() log = logging.getLogger() log.setLevel(logging.DEBUG)
GPIO.setmode(GPIO.BOARD) GPIO.setup(7,GPIO.OUT,initial=GPIO.LOW)
client= ModbusClient(method = 'rtu', port='/dev/ttyS0',stopbits = 1,timeout =0.3, bytesize = 8, parity = 'N', baudrate = '9600')
connection = client.connect()
print "Connection" print connection
while 1:
volt=0 freq=0 if connection: try: voltage1= client.read_input_registers(0x000,4,unit=0x03) print voltage1 except: print "Error: No message Received" client.close()
And i am receiving the output as follows
DEBUG:pymodbus.transaction:Current transaction state - TRANSACTION_COMPLETE
DEBUG:pymodbus.transaction:Running transaction 4
DEBUG:pymodbus.transaction:SEND: 0x3 0x4 0x0 0x0 0x0 0x4 0xf0 0x2b
DEBUG:pymodbus.framer.rtu_framer:Changing state to IDLE - Last Frame End - None, Current Time stamp - 1557304284.88
DEBUG:pymodbus.client.sync:New Transaction state 'SENDING'
DEBUG:pymodbus.transaction:Changing transaction state from 'SENDING' to 'WAITING FOR REPLY'
DEBUG:pymodbus.transaction:Changing transaction state from 'WAITING FOR REPLY' to 'PROCESSING REPLY'
DEBUG:pymodbus.transaction:RECV: 0x7b 0x20 0x31 0x20 0x31 0x20 0x32 0x36 0x2e 0x33 0x35 0x20 0x31
DEBUG:pymodbus.transaction:Changing transaction state from 'PROCESSING REPLY' to 'TRANSACTION_COMPLETE'
Modbus Error: [Input/Output] No Response received from the remote unit/Unable to decode response
DEBUG:pymodbus.transaction:Current transaction state - TRANSACTION_COMPLETE
DEBUG:pymodbus.transaction:Running transaction 5
DEBUG:pymodbus.transaction:Clearing current Frame : - 0x7b 0x20 0x31 0x20 0x31 0x20 0x32 0x36 0x2e 0x33 0x35 0x20 0x31
DEBUG:pymodbus.framer.rtu_framer:Resetting frame - Current Frame in buffer - 0x7b 0x20 0x31 0x20 0x31 0x20 0x32 0x36 0x2e 0x33 0x35 0x20 0x31
DEBUG:pymodbus.transaction:SEND: 0x3 0x4 0x0 0x0 0x0 0x4 0xf0 0x2b
DEBUG:pymodbus.framer.rtu_framer:Changing state to IDLE - Last Frame End - None, Current Time stamp - 1557304284.98
DEBUG:pymodbus.client.sync:New Transaction state 'SENDING'
WARNING:pymodbus.client.sync:Cleanup recv buffer before send: 0x37 0x2e 0x35 0x35 0x20 0x33
DEBUG:pymodbus.transaction:Changing transaction state from 'SENDING' to 'WAITING FOR REPLY'
DEBUG:pymodbus.transaction:Incomplete message received, Expected 13 bytes Recieved 7 bytes !!!!
DEBUG:pymodbus.transaction:Changing transaction state from 'WAITING FOR REPLY' to 'PROCESSING REPLY'
DEBUG:pymodbus.transaction:RECV: 0x2e 0x30 0x36 0x20 0x7d 0xd 0xa
DEBUG:pymodbus.transaction:Changing transaction state from 'PROCESSING REPLY' to 'TRANSACTION_COMPLETE'
Modbus Error: [Input/Output] No Response received from the remote unit/Unable to decode response