PLC CONNECTION HELP NEEDE

[Rushil sevak]

Thank you in Advance.

I am very good in PLC logic & programming, but new to python.

I have mitsubishi make PLC which is GOC35.
want to connect via mosbustcp using python pymodbus library.

i am already test this PLC connection via Tcpip modbus with SCADA.
but now want to connect using python script & pymodbus library.

I started this but not getting any response from PLC & also check ping from PLC in CMD it is working ok.
below is my code.

from pymodbus.client.sync import ModbusTcp lient

client = ModbusTcpClient('192.268.1.11')
client.read_holding_registers(0,3).registers

it gives me 'modbusioexception' & registers in not module.

Please guide me to solve this.

so, please guide me where to start.

[Akash Banaulikar]

Hello rushil
You can use
client = ModbusTcpClient(host='192.268.1.11',port=)
register=client.read_holding_registers(address=0,count=1,unit=1)
registerstore=register.registers[0]

In your case you need to provide proper count value and plc unit number and client. read_holding_registers reads multiple registers and stores in a list so use .registers[0]
This will display content of register at position 0.
And in connection string provide proper port number.
You can go to www.nakshautomation.live for more details

[Rushil sevak]

Sure Mr. Akash  i will check & get back t you Thank you for your prompt reply.

[Rushil sevak]

By doing this i am getting this error also attached screen short here please guide me.

On Monday, 11 May 2020 00:09:49 UTC+5:30, Akash Banaulikar wrote:

[Akash Banaulikar]

For pymodbus to read ypur plc tags you must provide address, count, unit of plc.
register=client.read_holding_registers(address=0,count=1,unit=1)
Like this.

[Akash Banaulikar]

client = ModbusTcpClient(host='192.268.1.11',port=502)
And put host = which is missing in tour case

[Rushil sevak]

Thank you very much Sir,

i got out put which is attached but i want to know something more about address, count & unit.

can you please explain me it in detail ?

[Akash Banaulikar]

register=client.read_holding_registers(address=0,count=1,unit=1)
address is the modbus address of plc which you want to read.
Count is number of registers you want to read.
For eg. You are reading data from modbus address 0 and count value is 1 then you will get the value of only 0th modbus address and suppose count is 3 then you will get data from modbus address 0,1,2 and it will be stored in a list

For direct PLC supporting Modbus/TCP, set the Unit ID to zero (or
one). The PLC likely ignores it.

[Rushil sevak]

Thank you,

now can i connect this script with mysql database?

[Akash Banaulikar]

yes you can use sqlserver.
Please visit www.nakshautomation.live
There are tutorials for sending plc data to database via pymodbus

[Rushil sevak]

I go to website but unfortunately advertisement not open any tutorial sir.

if possible please give steps overhyere or suggest other link.

Thank you.

[Akash Banaulikar]

okay.
You can use sql server database.
conn = pyodbc.connect("Driver={ODBC Driver 11 for SQL Server};"
"Server=LAPTOP-CNL636HF\SQLEXPRESS;"
"Database=pyscada;"
"Trusted_Connection=yes;")
# connection start
cursor = conn.cursor()
now=datetime.now()
formatted_date=now.strftime('%Y-%m-%d %H:%M:%S ')

# to insert data into database
cursor.execute('insert into pytb2(datetime,count) values(?,?)', (formatted_date,regs1) )
conn.commit()
conn.close()
Reg1 stores plc register value
To know which driver server to use to make connection please visit
https://www.nakshautomation.live/pyhmi#top

[Rushil sevak]

Ok sir,

i got this from your side, Thank you very much for that,

now i want to get data from the modbus serial communication using python so can you suggest me from where i have to start.

i started but get following errors i also attached pic of that over here please guide me sir,,

Thank you in advance.