OPC & PLC Integration

[Sathiyraj]

Hi All,

we have an project which is using Very old PLC/Controller. Even we are not able to find the Device Model & brand.

But my company required to get some Data from that Controller to IIOT Device. Recommended me to use OPC UA to collect Details from PLC.

Did Explained that Can't make it without knowing the Parameter Details like Memory address & Data Type of the DATA inside the PLC. Still they insisted me to do that.

Any Possible way available to Integrate parameters of PLC through Modbus without knowing the Memory Address & Data Type of it.

 

Regards,

 

Sathiyaraj

[Jay Anthony]

What PLC?  What style of hardware connection?  Need some basic specifications? 

[Sathiyraj]

On 4/28/2018 at 5:10 AM, Jay Anthony said:

What PLC?  What style of hardware connection?  Need some basic specifications? 

Yes, You are right.

But I have another Question as below.

If PLC Model & Hardware Connection Details available, Is it Possible to Access the DATA Values from PLC without knowing its Memory address?

 

Many Thanks.

[innoaloe]

7 hours ago, Sathiyraj said:

Yes, You are right.

But I have another Question as below.

If PLC Model & Hardware Connection Details available, Is it Possible to Access the DATA Values from PLC without knowing its Memory address?

 

Many Thanks.

No... And in most cases it's very hard to interface old PLC to OPC UA. You will need to implement some hardware-in-the-middle to do it, which is sometimes another PLC also. Depending on the machine, sometimes it is easier and more cost effective by replacing the existing PLC with a newer generation which is connectable with OPC UA.

[DanW]

I will freely make the statement that OPC UA will NEVER work with an unknown PLC with unknown data registers and unknown data properties.

You can't even get OPC DA to work with an unknown PLC with unknown data registers and unknown data properties. 

Hardware connection details do not qualify as data properties.   There is zero basis for accomplishing digital communications.

The basis for data communication is to know and understand the properties of the field data and then create/use/buy a digital communications protocol and associated bus hardware to accomplish data transfer and whatever software/firmware is needed for data interpretation at the other end.

The lack of understanding and knowledge about the data and its propertied precludes/exludes/eliminates the reasonablness of  attempting any type of digital communications.

As to unreasonable expectations, I like the signature line of a water processing expert - "Any water can be made potable if you filter it through enough money".    The same applies to any task, but is it worthwhile compared to the alternative - outright replacement?  

[Sathiyraj]

14 hours ago, innoaloe said:

No... And in most cases it's very hard to interface old PLC to OPC UA. You will need to implement some hardware-in-the-middle to do it, which is sometimes another PLC also. Depending on the machine, sometimes it is easier and more cost effective by replacing the existing PLC with a newer generation which is connectable with OPC UA.

Thanks a lot

[Sathiyraj]

4 hours ago, DanW said:

I will freely make the statement that OPC UA will NEVER work with an unknown PLC with unknown data registers and unknown data properties.

You can't even get OPC DA to work with an unknown PLC with unknown data registers and unknown data properties. 

Hardware connection details do not qualify as data properties.   There is zero basis for accomplishing digital communications.

The basis for data communication is to know and understand the properties of the field data and then create/use/buy a digital communications protocol and associated bus hardware to accomplish data transfer and whatever software/firmware is needed for data interpretation at the other end.

The lack of understanding and knowledge about the data and its propertied precludes/exludes/eliminates the reasonablness of  attempting any type of digital communications.

As to unreasonable expectations, I like the signature line of a water processing expert - "Any water can be made potable if you filter it through enough money".    The same applies to any task, but is it worthwhile compared to the alternative - outright replacement?  

Thanks for the Explanation.