#!/usr/bin/python

PROXIMITY = 5 #if requested registers are PROXIMITY from each other, combine the requests into one

from pymodbus3.client.sync import ModbusTcpClient

import argparse

import re

import datetime

from time import sleep

import signal

import sys

#listen for control-c to exit our polling loop

def signal_handler(signal, frame):

print('\nExiting!')

sys.exit(0)

signal.signal(signal.SIGINT, signal_handler)

#parse command line arguments

parser = argparse.ArgumentParser()

parser.add_argument('ip_address', type=str, help='IP address of Modbus TCP server')

parser.add_argument('registers', type=str, help='Comma seperated string of registers to read, the first character of each address indicates the type of register (0=Coil, 1=Discreet Input, 3=Input Register, 4=Holding Register)')

parser.add_argument('-v', '--verbose', action='store_true', help='Increase output verbosity')

parser.add_argument('-u', '--unit', type=int, default=1, help='Modbus unit id (default is 1)')

parser.add_argument('-p', '--port', type=int, default=502, help='Modbus port to connect to (default is 502)')

parser.add_argument('-i', '--interval', type=int, default=1000, help='Read interval in milliseconds (default is 1000)')

parser.add_argument('-f', '--file', help='Filename to output data to')

parser.add_argument('-s', '--separator', default=',', help='Separator character (default is ,)')

args = parser.parse_args()

registerList = [] #requested registers

readList = [] #requested registers combined into the few need requests

#build up readList combining requests where possible

p = re.compile('^(\d)(\d+)$')

for r in args.registers.split(','):

a = p.match(r.strip())

if a:

nr = {'type': int(a.group(1)), 'address': int(a.group(2)), 'count': 1}

registerList.append(nr)

for ri in readList:

if ri['type'] == nr['type']:

if (nr['address'] < ri['address']) and (ri['address'] <= nr['address'] + PROXIMITY):

ri['count'] += ri['address'] - nr['address']

ri['address'] = nr['address']

nr = None

break

elif (nr['address'] > ri['address']) and (ri['address'] + ri['count'] > nr['address'] - PROXIMITY):

ri['count'] = max(ri['count'], nr['address'] - ri['address'] + 1)

nr = None

break

if nr:

readList.append(nr)

#debugging output

if args.verbose:

print(registerList)

print(readList)

#create modbus client

client = ModbusTcpClient(args.ip_address, args.port)

#read modbus data

data = {}

lastFilename = ''

while True:

for ri in readList:

result = '-'

if ri['type'] == 0:

result = client.read_coils(ri['address'], ri['count'], unit=args.unit)

if ri['type'] == 1:

result = client.read_discrete_inputs(ri['address'], ri['count'], unit=args.unit)

if ri['type'] == 3:

result = client.read_input_registers(ri['address'], ri['count'], unit=args.unit)

if ri['type'] == 4:

result = client.read_holding_registers(ri['address'], ri['count'], unit=args.unit)

if ri['type'] < 2 and result != '-':

i = 0

for r in result.bits:

data[str(ri['type']) + '_' + str(ri['address'] + i)] = str(int(r))

i += 1

if ri['type'] > 2 and result != '-':

i = 0

for r in result.registers:

data[str(ri['type']) + '_' + str(ri['address'] + i)] = str(int(r))

i += 1

#get current time for timestamp and file naming

curTime = datetime.datetime.now()

output = curTime.strftime('%Y-%m-%d')

output += ',' + curTime.strftime('%H:%M:%S')

for r in registerList:

output += ',' + data[str(r['type']) + '_' + str(r['address'])]

#if file name specified, output to file creating/overwriting files as needed

if args.file:

fileName = curTime.strftime(args.file)

if lastFilename == '':

lastFilename = fileName

file = None

if lastFilename != fileName:

file = open(curTime.strftime(args.file), 'w+')

lastFilename = fileName

else:

file = open(curTime.strftime(args.file), 'a+')

file.write(output + '\n')

file.close()

else:

print(output)

#pause for milliseconds specified in interval argument

sleep(args.interval / 1000)

client.close()