Fast Timer

[eedhto]

Hi,

I am doing a PLC project and I need to check the status of my IOs by polling my parallel Port very often. I thought of using the Timer control component of Visual Basic but unfortunately is not that fast. It says that you can select interval of 1ms but basically is an interval of 52ms!

Is there any component I can use so that I can poll my parallel port almost every 1ms? I have seen that there is an ActiveX component from Mabry.com called HitTime but unfortunately it is not fo free.

Please advice and many thanks for your help.
H.

[rabbit_q]

hi, eedhto,

i'm also facing the same problem with yours, and quite my project is quite time pressed.

have you find any better solution yet? hope we are lucy enough to find a solution.

how abt let's keep in touch if anything is found? let's help each other since we're looking for the same thing.

Bon chance!

[rabbit_q]

btw, my email is [email protected]

if any info, all friends and pass-by please email to me. Rabbit thanks you all!

[eedhto]

I haven't found anything yet. I am still looking around. I have also some problems with ActiveX components. I have downloaded some evaluation versions from the Internet and they have time Limits. Any ideas how can I overcome the problem with the time limit without buyig a license?

[Phenglai]

I use them for timers in almost all of my applications and they work in my apps. The time is going to depend on what is running in the background. If you have lots running on the machine, Windows is going to have a hard time getting back to the timer every 1ms. I have used them successfully down to 10ms but you need to have no services running. My development machine is about as stripped down as it could be with only about 3 services running in the systray and not much else in memory.

I have tried other timers and they are not any better just based on the fact that 1ms is pretty quick for windows to get back to the timer.

Jerel

[rabbit_q]

although this timer has accuracy of 1ms. but it can only trigger 18.2 times per second, so it's more than 50ms.
that's not sufficient for a lot of application.
however, you are right, when the cpu has other things on, it cannot even reach 100ms response time.
i'm so sad.

[rabbit_q]

eedhtoC i've had a few reponse from other threads in this board concerning fast timer:

1. use API (search for timer in API forum)

2. use winmm.dll

you'll be happy to find these solutions.

there's another control called ccrp timer. if you can find it, it works its accuracy, from what i saw on demo, is up to 10ms.

[eedhto]

so, you think that the HitTime Software Program is not that good or accurate for time critical applications? Do you have any code examples of how to use the API you mentioned or the .dll file?

Please send them to me.

[rabbit_q]

i didnt copy down. you may do a search at the forum using 'timer ' + 'API'

you can find a few pieces of code.

however, some of them us a do while loop which will drain up the CPU resources.