CODEWITHSUNDEEP
pythonclient-serveropcopc-da
Mohamad Ibrahim
Mohamad Ibrahim

Reputation: 315

How can i transfer data from python to opc da server?

I have written a code in PYTHON. I want to transfer the respective outputs to OPC DA server so that clients can access it from the explorer. Can I create an empty configured aliases where I can fill it with my values and then display it or any similar logical easy solution ? the only way I figured out was to transfer the output data to a simulated item but that is not really a solution since I only want to show my data..

Upvotes: 1

Views: 4835

Answers (2)

ZbynekZ
ZbynekZ

Reputation: 1608

Code for manipulation values through OPC DA, similar to the answer from @john-hedengren , but with the use of QuickOPC library:

import opclabs_quickopc
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.OperationModel import *

client = EasyDAClient()

try:
    IEasyDAClientExtension.WriteItemValue(client, '', 'Kepware.KEPServerEX.V5', 'Channel2.Device1.T_12_Load_AVG', Load1_avg)
    IEasyDAClientExtension.WriteItemValue(client, '', 'Kepware.KEPServerEX.V5', 'Channel2.Device1.T_21_Load_AVG', Load2_avg)
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message, sep='')
    exit()

OPC UA (Unified Architecture) would require some changes, but the code would be similar in principle.

Upvotes: 0

John Hedengren
John Hedengren

Reputation: 14386

You can transfer values with MODBUS or OPC. You can do this with OpenOPC or PyOPC but you may want to use the newer OPC-UA standard. There is a well-developed Python package for OPC-UA. Here is example code with OpenOPC if you do need to use the older DA standard.

# #######################################
# OPC write
# #######################################
try:
    # OPC connection
    import OpenOPC
    opc=OpenOPC.client()
    b=opc.connect('Kepware.KEPServerEX.V5')
    #opc.connect('Kepware.KEPServerEX.V5','localhost')

    Load1_avg  = opcm[0][0]
    Load2_avg  = opcm[0][1]

    opc.write( ('Channel2.Device1.T_12_Load_AVG',Load1_avg) )
    opc.write( ('Channel2.Device1.T_21_Load_AVG',Load2_avg) )

    opc.close()
except:
    print 'OPC communication failed'
    pass

I've used this successfully with a Kepware server on several applications.

Upvotes: 0

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