答复: What is the maximum frequency for db scan?

[汪启胜 <wangqisheng@sinap.ac.cn>]

Title: 答复: What is the maximum frequency for db scan?

Hi, Thanks. I will try to adjust the frequency.

===================================================
Wang Qisheng 汪启胜
No.239 Zhangheng Road
PuDong District
Shanghai Institute of Applied Physics CAS
Shanghai, China
Tel: +86-21-33933256  Fax: +86-21-33933031



-----Original Message-----
From: Dirk Zimoch [mailto:dirk.zimoch@psi.ch]
Sent: 2009-6-2 (星期二) 18:07
To: 汪启胜
Cc: tech-talk@aps.anl.gov
Subject: Re: What is the maximum frequency for db scan?

Hello Qisheng

You can just define your own menuScan with higher frequencies. Make sure that
the clock of your IOC can handle that frequency. For example on vxWorks use
sysClkRateSet() to increase the system clock frequency.

The other possibility is to use "I/O Intr" scanning. In that case your driver
must trigger the scanning. If your hardware generates interrupts you can use as
a trigger for scanning, it should not be a problem. Call scanIoRequest() from
the interrupt service function. You can do this as fast as the CPU load allows.

Dirk

汪启胜 wrote:
>
> Hello, every one.
>
> Normally the da scan frequency is 0.1s, I want to know how to chang and
> what is the maximum value. For the data acquisition hardware the
> internal clock is very fast, from some threads it is said the vxWorks
> and Epics can handle 60Hz or 100Hz in maximum. Is it possible to
> breakthrough the limit?
>
> Thanks for your any suggestion.
>
> ===================================================
> Wang Qisheng 汪启胜
> No.239 Zhangheng Road
> PuDong District
> Shanghai Institute of Applied Physics CAS
> Shanghai, China
> Tel: +86-21-33933256  Fax: +86-21-33933031
>

--
Dr. Dirk Zimoch
Paul Scherrer Institut, WBGB/006
5232 Villigen PSI, Switzerland
Phone +41 56 310 5182