[2008] COM ports, timers and relays HELP!

I am putting together a relay timing program that is going to control 16 different relays, with at least 2 on/off points each daily.

This program is going to run 24/7. Each on/off point is going to be user selected by a DateTimePicker (time only. no date). I want to set the timer intervals that trigger my relay on/off commands to only fire when needed, if possible because when you try to manually activate the relay with a on/off button, the relay command associated with the timer is still active and firing every timer interval, thus making the button useless. It also ties up the network with "useless" traffic.

I started making a program but with 32+ timers it was getting a little confusing and the network was very busy. Can this be done with only a couple of timers? ...And if so can they only fire when needed so I can have an On/Off button option?

BTW, I'm shooting for a timer interval of 1-2 seconds (5 seconds if need be)

Here is a basic timing program I made with 2 on/off timers and an on and an off button

If someone can show me this in detail (and i mean in great detail because what you see below is nearly the extent of my VB skills...I mean like edit a copy of my code and post it. lol ) I would greatly appreciate it.

Code:

---

Public Class Form1
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Dim t As Date                              'timer 1 ON/OFF
        t = Date.Now
        If t > DateTimePicker1.Value And t < DateTimePicker2.Value Then
            TurnOnRelay()
        Else
            TurnOffRelay()
        End If
    End Sub
    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Dim t As Date                                'timer 2 ON/OFF
        t = Date.Now
        If t > DateTimePicker4.Value And t < DateTimePicker3.Value Then
            TurnOnRelay()
        Else
            TurnOffRelay()
        End If
    End Sub

    Private Sub TurnOnRelay()    'Relay 1 ON command
        Dim data(0 To 3) As Byte
        data(0) = 254
        data(1) = 108
        data(2) = 1
        SerialPort1.Write(data, 0, 3)
    End Sub

    Private Sub TurnOffRelay()      'Relay 1 OFF command
        Dim data(0 To 3) As Byte
        data(0) = 254
        data(1) = 100
        data(2) = 1
        SerialPort1.Write(data, 0, 3)
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        TurnOnRelay()                    ' On Button
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        TurnOffRelay()                    'Off Button
    End Sub
End Class

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I'd think you can get away with 1 timer for each relay and 1 "master" timer to start the relay's timer. And here is the sketch:

1. Use a 2-d Date array to store the start and stop time of each relay.

2. The master timer interval can be set to 1 second. In the Tick event handler, you check the current time to the relays' start time's, it they equal, do:
a) set that relay's timer.interval = the timespan of (stop time - start time)
b) relay's timer
c) turn on the relay

3. In each relay's timer tick event handler, you do:
a) stop the timer
b) turn off the relay.

In other words, the master timer will handle turning on the relays and starting the relay timers. Individual relay timers will turn of the relay and stop itself.

1. What kind of resolution for on / off times, meaning how exact are the on / off times, ms., secs., minutes, etc. If the resolution is 1-2 seconds and there are only 16 devices, one timer should suffice.

2. Is the command format
byte = 254
byte = 108 = on, 100 = off
byte = relay#

3. Make certain that you set the writetimeout for the serial port. The default is to wait indefinitely for the write to complete.

stanav, could you give me an idea of the VB commands to use?


dbasnett, I sent you an email earlier today regarding my previous post.

The resolution could be 1 minute max. I would much rather have a 1-5 second resolution if possible.

The command format is:

Byte: Description:
254 = Enter Command Mode
100 = Relay "0" OFF in specified bank (relay 1)
101 = Relay "1" OFF in specified bank (relay 2)
108 = Relay "0" ON in specified bank (relay 1)
109 = Relay "1" ON in specified bank (relay 2)
1 = *On relay bank 1

*all relays bank will be 1; There will be 8 different COM ports only using bank one and relay 1 & 2.

EDIT: Here is the Command Set PDF: http://www.electricdesignonline.com/...mand%20Set.pdf

Code:

---

    Const numRelays As Integer = 16
    Const ctOfRelays As Integer = numRelays - 1
    Dim relayA() As relays = New relays(ctOfRelays) {}
    Public Structure relays
        Dim relay As Byte 'relay id
        Dim comP As Byte 'com port ID
        Dim onTime As DateTime 'time on
        Dim offTime As DateTime 'time off
        Dim Rstate As Boolean 'on or off currently
    End Structure
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        For x As Integer = 0 To ctOfRelays
            If relayA(x).onTime >= DateTime.Now AndAlso relayA(x).offTime <= DateTime.Now Then
            Else
            End If
        Next
    End Sub

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dbasnett, How would I incorporate the datetimepicker and my relay on/off into this?


thanks