Calling .NET DLL Error

[ericmateovisan]

Hi everyone

I'm trying to make a TCP/IP connection with a PLC, using an open source DLL wrriten in .NET (This Library)

first of all I create an Action Step, and call the object ModbusClient and the Connect method: 

ModbusClient().Connect("device ip", port)

then I create the second Action Step, and call the WriteSingleCoil method to write a True status to Address 8193:

ModbusClient().WriteSingleCoil(8193,True)

after second step execution I get an exception error: connection error

it seems that first step execute independently and when the program execute the second step, the connected TCP/IP connection at the first step does not exist anymore.

I've read somewhere that we must store Object Reference in a Local variable and define it in the rest of the functions in different steps.. but I don't know what it means and don't know what to do..

I'm quite new to Teststand.. can anybody help ??

Thank you, Eric.

[IDASYAN]

Hi Eric jan,

Check this link, for the part of Local variables.

And also take a look at this, for TestStand.  

Regards.

[sezgin.caluk · Accepted solution]

Hi ericmateovisan, 

You can create first object  reference then  use "Use Existing Object(EasyModbus.ModbusClient).Connect(System.String, Int32)" in your next steps.  

1.   Create object   .NET Invocation = ModbusClient(), return value is object  reference

2.  .NET Invocation= Use Existing Object(EasyModbus.ModbusClient).Connect(System.String, Int32)

3.  .NET Invocation=  Existing Object(EasyModbus.ModbusClient).WriteSingleCoil(Int32, Boolean)

important point is here, that you need to use only existing object. 

check it please here  topic: Use Existing Object

https://www.ni.com/docs/en-US/bundle/teststand-api-reference/page/tsref/module-tab-edit-net-call-dia...

[ericmateovisan]

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@IDASYAN wrote:

Hi Eric jan,

Check this link, for the part of Local variables.

And also take a look at this, for TestStand.  

Regards.

---

Thank you for your reply 👌

[ericmateovisan]

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@IDASYAN wrote:

Hi Eric jan,

Check this link, for the part of Local variables.

And also take a look at this, for TestStand.  

Regards.

---

Thank you for your reply 👌

[ericmateovisan]

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@sezgin.caluk wrote:

Hi ericmateovisan, 

You can create first object  reference then  use "Use Existing Object(EasyModbus.ModbusClient).Connect(System.String, Int32)" in your next steps.  

1.   Create object   .NET Invocation = ModbusClient(), return value is object  reference

2.  .NET Invocation= Use Existing Object(EasyModbus.ModbusClient).Connect(System.String, Int32)

3.  .NET Invocation=  Existing Object(EasyModbus.ModbusClient).WriteSingleCoil(Int32, Boolean)

important point is here, that you need to use only existing object. 

check it please here  topic: Use Existing Object

https://www.ni.com/docs/en-US/bundle/teststand-api-reference/page/tsref/module-tab-edit-net-call-dia...

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thank you for your reply... this solved my problem. thank you so much 😊💙