Discussion:
Doubt using thr Read Tag .vi
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Giovani
2004-11-03 14:23:59 UTC
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I,m having some difficulty trying to understand the following:

The manuals I´ve read tell that to use the Read Tag.vi it´s not
necessary to previously start the Tag Engine using the Engine
Launch.vi.

But, when I try to read the value of a discrete tag using the Read
Tag.vi, the error output turns on. Because of this I decided to start
the Tag Engine usung the Engine Launch.vi before reading the tag but,
to my dismay, the error persisted.

Seeing this happen make me start to think that the problem was that
the engine hasn´t yet initialized when the Read Tag.vi ran; so, I
decided to wait an certain amount of time - in this case, 4000 ms
would suffice - before reading the tag value and, with this, no error
occurred. Could anyone pelease tell me if my assumption is correct ?
If not, why is this happening ?

PS :

It´s necessary to wait the time interval just the first time the tag
is read. Afterward, no errors occur.
Ben
2004-11-04 13:20:32 UTC
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Hi Giovani,

I believe you are correct in your work so far.

The tag engine takes some time to start. I seem to remeber an
applicatin with 6000 tags taking a minute or more to start up.

You can use the "Get Engine Status.vi" to determine when the engine is
up and running. This will work more reliably that a fixed wait time.

So,

You are correct!

Ben

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