# python -m pip install pyModbusTCP for Windows
# sudo pip3 install pyModbusTCP for Raspbian
# https://pypi.org/project/pyModbusTCP/

import struct
from pyModbusTCP.client import ModbusClient
from time import sleep
import sys

print (sys.version)
print()

AKD = ["192.168.0.1", "192.168.0.2", "192.168.0.3"]
client = [0,0,0]

def padded_hex(i, l):
    given_int = i
    given_len = l

    hex_result = hex(given_int)[2:] # remove '0x' from beginning of str
    num_hex_chars = len(hex_result)
    extra_zeros = '0' * (given_len - num_hex_chars) # may not get used..

    return ('0x' + hex_result if num_hex_chars == given_len else
            '?' * given_len if num_hex_chars > given_len else
            '0x' + extra_zeros + hex_result if num_hex_chars < given_len else
            None)

def GetValue(_rr):
    word0=padded_hex(_rr[0],4)
    word1=padded_hex(_rr[1],4)
    word2=padded_hex(_rr[2],4)
    word3=padded_hex(_rr[3],4)
    
    val1=word0[2:len(word0)]+word1[2:len(word1)]+word2[2:len(word2)]+word3[2:len(word3)]
    val2=int(val1,16)
    return -(val2 & 0x80000000) | (val2 & 0x7fffffff)
    
ADDR_PL_FB = 588

for i in range(0,3):
    client[i] = ModbusClient(host=AKD[i], port=502, auto_open=True, auto_close = True, timeout=1, unit_id=i)

while True:
    for i in range(0,3):
        rr = client[i].read_holding_registers(ADDR_PL_FB, 4)
        if rr:
            pos=GetValue(rr)
            print("Pos" + str(i) +"=" + str(pos))
    print()
    sleep(1)