Messages

1

Open Discussion / Re: ModbusTCPCom1.DisableSubscriptions = True not Working

« on: March 19, 2023, 03:32:11 PM »

I did that and it works fine. I thought disabling the subscriptions meant disconnecting altogether.

Anyway, thanks for the help.

2

Open Discussion / ModbusTCPCom1.DisableSubscriptions = True not Working

« on: March 19, 2023, 11:13:37 AM »

Overview: I have an ESP-01 programmed using the ModbusIP_ESP8266.h library. The AHMI can read and write the registers without issue. I am using 12 basic buttons to set the register bits and 12 pilot lamps to give register state feedback. But there is something that's confusing me about the connection.

I have two buttons that Enable and Disable the ModbusTCPCom1 connection.

Enable = ModbusTCPCom1.DisableSubscriptions = False
Disable = ModbusTCPCom1.DisableSubscriptions = True

Oddly though, after I disable the subscriptions the program is still able to communicate with the external device when I use the basic buttons to change register values. The pilot lamps however do not respond to the changes.

Can anyone here explain why this happens?

I hope I gave enough detail. If not I can give more. Thanks.

3

Support Questions / Re: ModbusTCP : Unable to write to a register

« on: September 15, 2021, 08:35:36 PM »

Just to add, I am using V3.99v if that helps.

Tried this as well to see if an error was thrown. Alas, nothing.

Code: [Select]

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Try
            ModbusTCPCom1.Write("40003", 2)
        Catch ex As Exception
            System.Windows.Forms.MessageBox.Show("Couldn't write to PLC. Error: " & ex.Message)
        End Try
    End Sub


4

Support Questions / ModbusTCP : Unable to write to a register

« on: September 15, 2021, 07:38:49 PM »

This is my first post so forgive me if I mess this up.

I am using ModbusTCP to communicate with an Arduino via Ethernet using mudbus.h. (The correct spelling) I can read and write bit values and read register values without any issues. But for some reason I cannot write data to a register.

I would like to read a text file and send the values to two registers when the program starts. These values represent offset values for two TOF sensors connected to the Arduino.

I am hoping to be able to use them to line up my two Y Axis stepper motor positions on my CNC gantry and use the offsets to allow for any mounting errors.

Code: [Select]

Private Sub MainForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        If My.Computer.FileSystem.FileExists("C:\axis_offsets.txt") Then

            Dim reader As New System.IO.StreamReader("C:\axis_offsets.txt")

            Dim MyValue1, MyValue2 As String

            MyValue1 = reader.ReadLine()
            Dim CurrentValueInt1 As Integer = CInt(MyValue1)

            MyValue2 = reader.ReadLine()
            Dim CurrentValueInt2 As Integer = CInt(MyValue2)

            reader.Close()

            ModbusTCPCom1.Write("40003", CurrentValueInt1)
            ModbusTCPCom1.Write("40004", CurrentValueInt2)

        Else
            Dim writer As New System.IO.StreamWriter("C:\axis_offsets.txt", False)
            writer.WriteLine(0)
            writer.WriteLine(0)
            writer.Close()
        End If
    End Sub

This button click code will not work either.

Code: [Select]

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        ModbusTCPCom1.Write("40003", 2)
        ModbusTCPCom1.Write("40004", 2)
    End Sub

If I could figure out a way to use an ESP8266 with AHMI, I'd give it a go. Save me the problem of storing offsets on my computer and saving them on the ESP8266.

I'm a recently retired Industrial Electrician (Canada) so maybe I'm just getting old and missed something simple?

Thank you for any help one of you can provide. It would be deeply appreciated.