AdvancedHMI Software

General Category => Support Questions => Topic started by: scott.clark on April 14, 2021, 05:36:55 PM

Title: ModbusTCPCom1.write returns a value, what is it?
Post by: scott.clark on April 14, 2021, 05:36:55 PM

When executing:

Code: [Select]

dim strReturn as string
 strReturn = ModbusTCPCom1.write(PLCTagAddress,Value)

What does the value returned represent?  its typically a varying number between 250 and 300.

I was looking for a way to detect when the target PLC is not communicating. 

With a ModbusTCPCom1.read, if there is no communications, there is and exception the can be handled with at Try/Catch.

I haven't been able to figure out how to validate that a ModbusTCPCom1.write is successful.

Title: Re: ModbusTCPCom1.write returns a value, what is it?
Post by: Alpaslan on May 01, 2021, 08:21:20 PM

Try this.

Quote

       Try
         ModbusTCPCom1.write(PLCTagAddress,Value)
       Catch ex As Exception
           System.Windows.Forms.MessageBox.Show("Couldn't write to PLC. Error: " & ex.Message)
       End Try

Title: Re: ModbusTCPCom1.write returns a value, what is it?
Post by: Archie on May 05, 2021, 11:21:51 PM

The value returned is a transaction ID that can be used in the Error and DataReceived events.

Title: Re: ModbusTCPCom1.write returns a value, what is it?
Post by: scott.clark on May 11, 2021, 09:38:43 AM

Thanks for the explanation!