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fieldpoint scaling

Hi All,

We have just purchased a fieldpoint unit and have it working nicely under
test. But, I can not see anywhere in the fieldpoint explorer where you can
set span or scaling for the data (I have an 8 ch analogue input module).
Does Fieldpoint merely read voltages, and the rest is up to the programmer?
(I am programming in Labview)


Also, I noted in the Fieldpoint manual that it is reccomended not to have
more than one FP Advise Vi in any loop. Since Fieldpoint is capable of
having something like 225 (25 lots of 9) modules connected together (with
RS-485), Does this mean that you need 225 parallel loops to access all the
modules data. Is there a method where you can access all the input data on
one node (9 modules) with a sim
ple command?


Thanks
John
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"John" wrote:
>Hi All,>>We have just purchased a fieldpoint unit and have it working nicely
under>test. But, I can not see anywhere in the fieldpoint explorer where
you can>set span or scaling for the data (I have an 8 ch analogue input module).>Does
Fieldpoint merely read voltages, and the rest is up to the programmer?>(I
am programming in Labview)>>>Also, I noted in the Fieldpoint manual that
it is reccomended not to have>more than one FP Advise Vi in any loop. Since
Fieldpoint is capable of>having something like 225 (25 lots of 9) modules
connected together (with>RS-485), Does this mean that you need 225 parallel
loops to access all the>modules data. Is there a method where you can access
all the input data on>one node (9 modules) with a simple command?>>>Thanks>John>>>

The LabVIEW VI's will automatically return the scaled data based upon the
configuration that was specified in FieldPoint Explorer. For example, a FP-TC-120
can return data as voltages or as temperatures depending upon the configuration
of the channel.

The reason that it is not recommended to use more than one FP Advise in a
loop is because there is an option for On Change. If On Change is True, the
VI returns only when the state of the channel(s) monitored by that Advise
statement changes. This has the beneficial effect of allowing event driven
programming (putting loops to sleep while data is unchanging) but has the
side effect that, improperly used, it can cause the program to effectively
hang at the FP Advise. As an alternative, you can also use the FP Read.vi.
(does not have the On Change option). The main difference in use between
FP Read and FP Advise is that you use the FP Read for synchronous type operations
and the FP Advise for asynchronous type operation.

As for addressing, you can not access more than one module per FP Read/Write/Advise.
You can use the All channel which allows you to access all channels on a
single module, but the protocol used for communication does not allow multiple
module communication.

Regards,
Aaron Gelfand
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