Experimental Physics and
Industrial Control System

Luedeke Andreas <[email protected]> · Mon, 30 Jan 2006 10:05:15 +0100

Benjamin Franksen wrote:

On Saturday 28 January 2006 00:52, Chestnut, Ronald P. wrote:

If you do change the seq record (or make a new one), can you please
change the behaviour for a "0" delay? Now a new thread is started for
each (DOL/LNK) pair. If the delay is zero, can you "just do it" in
the same thread? We found that for some big "explosions" (nested
SEQs) the task switching dominates the processing time.

[...]

However, it /does/ request a callback for each group, regardless whether

the delay is zero or not, and this can indeed cause unnecessary context

switches. So, yes, I will change this. Adjacent link groups with zero

delay will be processed in a synchronous manner i.e. w/o requesting a

callback.

Thanks for the hint.

If I remember correctly the "seq" record is 100% asynchronous.

If you specify delays of "0", all DOLn links are supposed to be read at

the same time.

How do you want to do this without a callback?

(You need it to place the value into DOn when it's received and then

write it to LNKn.)

But of course it would be sometimes useful to have a synchronous process

chain,

where the next link is processed after the the previous one completed

and then the delay elapsed.

Regards
Andreas

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System