Experimental Physics and
Industrial Control System

Peregrine McGehee <[email protected]> · Fri, 9 Apr 2004 14:49:39 -0600 (MDT)

Andrew,

Does that mean the value transmitted via a caput() action is
discarded if the target record had PACT true due to being
in its "read" mode, for example, caused to process by a FLNK from
another record?

- Peregrine

On Fri, 9 Apr 2004, Andrew Johnson wrote:

> The talk of how to implement bidirectional I/O through existing record
> types still has a fundamental problem that *cannot* be solved using a
> single VAL field no matter how you implement it - you're going to throw
> away information somewhere if a new output demand occurs at about the same
> time as a new value comes back from the device.  You cannot simultaneously
> hold both a record's last output demand and the value read back from the
> device, unless this record provides the only possible way to change that
> output.  There is no substitute for having two different places to store
> the last demand and the readback information.
>

-- 
Peregrine M. McGehee	Department of Astronomy
New Mexico State University, Las Cruces, New Mexico

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System