Hi,
I am trying to implement modbus protocol on EM6400 in python to read values from energy meter.

Below here is more detailed explanation of my implementation:

Request:
01 03 0F56 0002 270F
01: Slave address
03: Function code for read holding registers
0F56: Data Address of the first requested register (address for voltage phase1 to neutral)
(0F56 hex = 3927, +40001 offset = 43928)
0002: Total number of registers requested
270F: CRC (Cyclic Redundancy Check) for error checking (LSB first)

Response:
01 03 04 2921 4373 D2B0
01: Slave address
03: Function code for read holding registers
04: Total number of bytes read
2921: Data in 1st requested register
4373: Data in 2st requested register
D2B0: CRC for error checking (LSB first)

Values in required register are 43732921 in hex (since obtained values are being read in little endian
format) which is 243.16 when converted to floating point using IEEE 754 norms. Obtained value is a
voltage (phase1 to neutral) which is 243.16 Volts.

Could i get a piece of code for the same as i am having difficulty in implementing this.Is it possible to implement this only by using Pyserial instead of Pymodbus.

Here is the piece of code, i tried
`import os
import sys
cwd=os.getcwd()
(setpath,Examples)=os.path.split(cwd)
print setpath
sys.path.append(setpath)

from PyArduino import *

import struct

port=locateport()
ser = serial.Serial(port, 9600)

ser.write("\x01\x03\x15\x86\x00\x02\x39\x15")
buf=ser.read(11)

b1=b2=b3=b4=0

a1=buf[3]

if (a1<16):
b1=1
a1=int(a1,16)
if (b1):
a1='0'+str(a1)

a2=buf[4]
if (a2<16):
b2=1
a2=int(a2,16)
if (b2):
a2='0'+str(a2)

a3=buf[5]
if (a3<16):
b3=1
a3=int(a3,16)
if (b3):
a3='0'+str(a3)

a4=buf[6]
if (a4<16):
b4=1
a4=int(a4,16)
if (b4):
a4='0'+str(a4)

a5=[a3,a4,a1,a2];
a6=''.join(a5)

print struct.unpack('!f', a6.decode('hex'))[0]

`
Regards,
Manas