Modbus TCP Slaver using Python modbus-tk lib

https://github.com/ljean/modbus-tk/

install pip…
sudo apt-get install python-pip

install...
download modbus_tk-x.x.x.tar.gz
tar zxvf modbus_tk-x.x.x.tar.gz
python setup.py install

make sure your port is open...
sudo iptables -A INPUT -p tcp --dport 502 -j ACCEPT # for slaver
sudo iptables -A OUTPUT -p tcp --dport 502 -j ACCEPT  # for master

run example as root
a simple example...

import sys
import logging
import threading
import modbus_tk
import modbus_tk.defines as cst
import modbus_tk.modbus as modbus
import modbus_tk.modbus_tcp as modbus_tcp
import time

logger = modbus_tk.utils.create_logger(name="console", record_format="%(message)s")
# CREATE server
server = modbus_tcp.TcpServer() #DEFAULT PORT=502
slaver = server.add_slave(1) #ID=1

def setup():
    slaver.add_block("coil", cst.COILS, 0, 16)
    slaver.set_values("coil", 0, 16*[0])

       
def loop():
    logger.info("running...")
    # START
    server.start()
    while True:
        values = slaver.get_values("coil", 0, 8)
        #print values[0]
        str = ''
        for i in range(0, 8):
            if values[i] == 1:
                str = str + '1'
            else:
                str = str + '0'
        print  str
        # DELAY
        time.sleep(1)
        
def destory():
    logger.info("destory")
    # STOP
    server.stop()
       
if __name__ == "__main__":
    setup()
    try:
        loop()
    except KeyboardInterrupt:
        destory()