Timer Control

**Allcomp** · Jul 17 '05, 09:31 PM

Re: Timer Control

Hello,

Personally, I use the windows API instead of a Timer

Public Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

I don't know if it is good or not, but I have been told that the timer
can slow down the computer, so I always use sleep instead of a timer.

You must just pay attention that the sleep will wait 0.1 sec for
example, but if the program between the sleeps last 0.05 sec, you will
have 0.15 seconds between 2 sleeps (the sleep and the following code) so
you must have a fast code between the sleeps (or use multi thread or
multi process)

Marc Allard
Allcomp

William Bub wrote:[color=blue]
> Is there an accurate way to create a "stopwatch" good to 1/10 of a second?
> I'm not sure if I should use the timer control, or some way to access the
> computer timer. I found the following site
> http://searchvb.techtarget.com/tip/1...535495,00.html
> which has the following:
>
>[color=green]
>>Want to really get down to instants? This tip from reader Phil Lenoir[/color]
>
> tells you how.
>[color=green]
>>--------------------------------------------------------------------------[/color]
>
> ------
>[color=green]
>>The only way you can access fractions of a second in VB is using a Timer,[/color]
>
> Right? Wrong.
>[color=green]
>>Use this simple technique to access time down to the resolution of the PC[/color]
>
> timer interrupt. It
>[color=green]
>>relies on the fact that Microsoft's internal time format is stored as a[/color]
>
> Double-precision number
>[color=green]
>> representing the number of years since 1900.
>>This code will pause for the requested fraction of a second:
>>
>>Public Sub Pause(dblHowLon g As Double)
>>Dim dblPauseUntil As Double
>>dblPauseUnt il = CDbl(Now) + dblHowLong
>>While cDbl(Now) < dblPauseUntil
>>DoEvents
>>Wend
>>End Sub[/color]
>
>
> I didn't use this directly, but I wanted to see the resolution ofCDbl(Now),
> so I tried
> the following:
>
> Private Sub tmrDispTime_Tim er()
> tmrDispTime.Int erval = 500
> fNum = fNum + 1
> txtNum = txtNum + CStr(fNum) + vbCrLf
> txtTime = txtTime + CStr(CDbl(Now)) + vbCrLf
> End Sub
>
> I expected this to show a different value every 500ms, but instead I
> received the following for fNum 1-17:
> 38487.901840277 8
> 38487.901840277 8
> 38487.901851851 9
> 38487.901851851 9
> 38487.901863425 9
> 38487.901863425 9
> 38487.901875
> 38487.901886574 1
> 38487.901886574 1
> 38487.901898148 1
> 38487.901898148 1
> 38487.901909722 2
> 38487.901909722 2
> 38487.901921296 3
> 38487.901921296 3
> 38487.901932870 4
> 38487.901944444 4
>
> Note that the timer events should come about 2 per second, and that the
> output seems to only change
> approx every other number, i.e. every second.
>
> If I use simply the timer event, and not the clock, how can I expect to
> update a display exactly 10 times per
> second, over 15 minutes or more? If each timer event restarted the timer for
> 100 ms, wouldn't there still be
> time lost between events?
>
>[/color]

**Steve Gerrard** · Jul 17 '05, 09:31 PM

Re: Timer Control

"William Bub" <fathafluff@hot mail.com> wrote in message
news:P7Uhe.3568 3$ia6.31372@twi ster.nyroc.rr.c om...
[color=blue]
> Is there an accurate way to create a "stopwatch" good to 1/10 of a second?[/color]

The basic idea for all timing is to use a timer to cause events to occur, but to
read a clock to get the elapsed time.The example below uses a timer called
Timer1, and also calls the Timer() function, so don't confuse the two. The
Timer() call returns elapsed seconds, and is good to between 5 and 50 msecs,
depending on the OS.

You can also use the API call GetTickCount, or even QueryPerformanc eCounter for
very precise timings.

Option Explicit

Private mStart As Single

Private Sub Form_Load()
Timer1.Enabled = False
' interval smaller than desired resolution
Timer1.Interval = 20
End Sub

Private Sub Command1_Click( )
If Timer1.Enabled Then
Timer1.Enabled = False
Me.Caption = Format(Timer() - mStart, "0.0")
Else
Timer1.Enabled = True
mStart = Timer()
End If
End Sub

Private Sub Timer1_Timer()
Me.Caption = Format(Timer() - mStart, "0.0")
End Sub

**SpeedBoy** · Jul 17 '05, 09:31 PM

Re: Timer Control

The standard Microsoft timer control is inherently inaccurate, even for
timing in 1/10th of a second intervals.

Mabry Software makes a high-resolution timer control (Hitime.ocx) that is
remarkably accurate down to (basically) 1/1000th of a second. I've used it
in numerous "critical" timing projects with terrific success. It's
reasonably priced, and easy to implement. A fully-functional demo version is
available at their website (www.mabry.com).

Frank Lewis
SpeedFoundry, Inc.

"William Bub" <fathafluff@hot mail.com> wrote in message
news:P7Uhe.3568 3$ia6.31372@twi ster.nyroc.rr.c om...[color=blue]
> Is there an accurate way to create a "stopwatch" good to 1/10 of a second?
> I'm not sure if I should use the timer control, or some way to access the
> computer timer. I found the following site
> http://searchvb.techtarget.com/tip/1...535495,00.html
> which has the following:
>[color=green]
> > Want to really get down to instants? This tip from reader Phil Lenoir[/color]
> tells you how.
>
> --------------------------------------------------------------------------
> ------[color=green]
> > The only way you can access fractions of a second in VB is using a[/color][/color]
Timer,[color=blue]
> Right? Wrong.[color=green]
> > Use this simple technique to access time down to the resolution of the[/color][/color]
PC[color=blue]
> timer interrupt. It[color=green]
> > relies on the fact that Microsoft's internal time format is stored as a[/color]
> Double-precision number[color=green]
> > representing the number of years since 1900.
> > This code will pause for the requested fraction of a second:
> >
> > Public Sub Pause(dblHowLon g As Double)
> > Dim dblPauseUntil As Double
> > dblPauseUntil = CDbl(Now) + dblHowLong
> > While cDbl(Now) < dblPauseUntil
> > DoEvents
> > Wend
> > End Sub[/color]
>
> I didn't use this directly, but I wanted to see the resolution[/color]
ofCDbl(Now),[color=blue]
> so I tried
> the following:
>
> Private Sub tmrDispTime_Tim er()
> tmrDispTime.Int erval = 500
> fNum = fNum + 1
> txtNum = txtNum + CStr(fNum) + vbCrLf
> txtTime = txtTime + CStr(CDbl(Now)) + vbCrLf
> End Sub
>
> I expected this to show a different value every 500ms, but instead I
> received the following for fNum 1-17:
> 38487.901840277 8
> 38487.901840277 8
> 38487.901851851 9
> 38487.901851851 9
> 38487.901863425 9
> 38487.901863425 9
> 38487.901875
> 38487.901886574 1
> 38487.901886574 1
> 38487.901898148 1
> 38487.901898148 1
> 38487.901909722 2
> 38487.901909722 2
> 38487.901921296 3
> 38487.901921296 3
> 38487.901932870 4
> 38487.901944444 4
>
> Note that the timer events should come about 2 per second, and that the
> output seems to only change
> approx every other number, i.e. every second.
>
> If I use simply the timer event, and not the clock, how can I expect to
> update a display exactly 10 times per
> second, over 15 minutes or more? If each timer event restarted the timer[/color]
for[color=blue]
> 100 ms, wouldn't there still be
> time lost between events?
>
>[/color]

**Tom** · Jul 17 '05, 09:32 PM

Re: Timer Control

If you are running Windoze Millenium, the timer control is
even slower.
I wrote an animated app at work (NT machine) and it
was moving quite well. I brought it home and tried it
with Millenium. It was so slow that I got bored watching.
At tht time, I had a dual boot machine. A reboot to Win2K
pro produced no problem.
I agree with the others, API calls are best for accurate timing.

Tom.

"William Bub" <fathafluff@hot mail.com> wrote in message
news:P7Uhe.3568 3$ia6.31372@twi ster.nyroc.rr.c om...[color=blue]
> Is there an accurate way to create a "stopwatch" good to 1/10 of a second?
> I'm not sure if I should use the timer control, or some way to access the
> computer timer. I found the following site
> http://searchvb.techtarget.com/tip/1...535495,00.html
> which has the following:
>[color=green]
> > Want to really get down to instants? This tip from reader Phil Lenoir[/color]
> tells you how.
>
> --------------------------------------------------------------------------
> ------[color=green]
> > The only way you can access fractions of a second in VB is using a[/color][/color]
Timer,[color=blue]
> Right? Wrong.[color=green]
> > Use this simple technique to access time down to the resolution of the[/color][/color]
PC[color=blue]
> timer interrupt. It[color=green]
> > relies on the fact that Microsoft's internal time format is stored as a[/color]
> Double-precision number[color=green]
> > representing the number of years since 1900.
> > This code will pause for the requested fraction of a second:
> >
> > Public Sub Pause(dblHowLon g As Double)
> > Dim dblPauseUntil As Double
> > dblPauseUntil = CDbl(Now) + dblHowLong
> > While cDbl(Now) < dblPauseUntil
> > DoEvents
> > Wend
> > End Sub[/color]
>
> I didn't use this directly, but I wanted to see the resolution[/color]
ofCDbl(Now),[color=blue]
> so I tried
> the following:
>
> Private Sub tmrDispTime_Tim er()
> tmrDispTime.Int erval = 500
> fNum = fNum + 1
> txtNum = txtNum + CStr(fNum) + vbCrLf
> txtTime = txtTime + CStr(CDbl(Now)) + vbCrLf
> End Sub
>
> I expected this to show a different value every 500ms, but instead I
> received the following for fNum 1-17:
> 38487.901840277 8
> 38487.901840277 8
> 38487.901851851 9
> 38487.901851851 9
> 38487.901863425 9
> 38487.901863425 9
> 38487.901875
> 38487.901886574 1
> 38487.901886574 1
> 38487.901898148 1
> 38487.901898148 1
> 38487.901909722 2
> 38487.901909722 2
> 38487.901921296 3
> 38487.901921296 3
> 38487.901932870 4
> 38487.901944444 4
>
> Note that the timer events should come about 2 per second, and that the
> output seems to only change
> approx every other number, i.e. every second.
>
> If I use simply the timer event, and not the clock, how can I expect to
> update a display exactly 10 times per
> second, over 15 minutes or more? If each timer event restarted the timer[/color]
for[color=blue]
> 100 ms, wouldn't there still be
> time lost between events?
>
>[/color]

Timer Control

Timer Control

Comment

Comment

Comment

Comment