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Fieldpoint cFP-1804 cFP-RTD-122 cFP-RTD-124 sample speed ?

I would like to know more about the equipment

cFP-1804, cFP-1808

8 inputs


8 inputs

connected to a Windows PC running Labview.

We need either 4 (option1) or 10 channels (optioin2) of temperature data, with a maximum sample rate of 10 Hz for each channel,
for a test bed for electric motors in a laboratory. The data aquisition time is 24 hours, we need a "continous data recording" mode both with the data aquisiton driver/hardware and with Labview. The Labview PC itself controls the motor and brake system, by special devices connected by GPIB bus.

One offer by a test bed manufacturer is to use this Fieldpoint equipment with serial connection,

while we would prefer
* either to wait some months and take a cDAQ solution after the forthcoming and announced release of the drivers for NI 9217
 RTD Module for the cDAQ platform
* take an Ethernet TCP/IP connection for the communication between .cFP-1804 and Labview PC.

Well why do we want to use the "dumb" Fieldpoint backplane ? It is the cheapest Fieldpoint solution and the compiled Labview software of the test bed manufacturer does not support other devices so far. Alternatively we just buy the testbed and write the Labview software by ourselves.....

We know with cDAQ, we might use a "hardware loop" so that the sample speed is guaranteed by the cDAQ device, and that Labview runs in a loop which is just activated after a block of data arrived.

Can the dumb fieldpoint backplanes cFP-1804, cFP-1808 with the temperature input modules cFP-RTD-122,  cFP-RTD-124 do that "hardware loop" with sample rates, guaranteed by the hardware, up to each 10 Hz too, for 4 or 10 channels?

Indeed, are there free DAQmx drivers for accessing the data by cFP-1804, with all usual options like "continous recording" of data, or is there a different way to get the data ( direct VI devices which can read the serial port or TCP/IP port ) ?

We were told so far, that we must use the "Timded Loop", so that Labview must guarantee the sampling rate.
And that Labview must call any data from the Fieldpoint devices, i.e.that it must call for a temperature A/D conversion for each requested data.
Is that true ? ( of course with very-cheap USB data aquisition boxes like 6009 this is true.) .It would be a burden for Labview !???!

And if so, does measuring 10 channels cost more time than measuring 1 or 4 channels ?

Is the (serial) transfer the typical bottleneck of the Fieldpoint system if used for data aquisition ? Is the built in TCP/IP Ethernet solution  so much better ?

What is the maximum sample speed I can get with
dumb fieldpoint backplanes cFP-1804, cFP-1808
with the temperature input modules cFP-RTD-122,  cFP-RTD-124, and how is speed affected by the number of channels
As this Fieldpoint device might be the base for further test experiments with need for higher sample speeds.

For comparison cDAQ with forthcoming drivers for NI9217 module supports up to 100 Hz/Channel, AFAIK.
So 4 channels with 100 Hz, or 10 channels with 100 Hz should be no problem...

Can you recommend to use the Fieldpoint system and NOT the cDAQ system and NOT a PCI card system,
if yes by what reason ?
And can you really recommend Fieldpoint for our problem ?

Is there a comparison chart about the maximum sample / transfer rates of
NI PCI cards
NI Fieldpoint
, with the number of used channels as parameter ?

Rolf Hemmerling

Message Edited by hemmerling on 01-11-2007 12:08 AM

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Hi Guys,

Thanks for your help.  Tommy is coorect.  The same AI-110 module has channels with timestamps that are hours, minutes and seconds different.  There are a quantity of three (3) cFP-2120 modules on the same subnet each with theri own static IP address.  cFP-2120-A has one AI-110.  cFP-2120-B has three AI-110 and cFP-2120-C has one AI-110.  Each cFP has their own backplane.  Each cFP has the LV development PC as the time server (again a static IP).

I will write down some data to clearly show the issue that I have.

I also have come across another question:  When one looks at all of the channels on the cFP-2120, you see the LEDs, Power (which source), Digital I/O  There is another one called 'Temperature'.  Is there a tmeperature sensor on the cFP-2120?  I don;t recall reading this in the manual.

Thanks again,


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Sorry this last message is off-topic and does not answer my questions.
Have another try

Additional Question:
What is the maximum sample speed I can get with
dumb fieldpoint backplanes cFP-1804, cFP-1808
with any input or output module ( so not just with temperature input modules cFP-RTD-122,  cFP-RTD-124),
and how is speed affected by the number of channels

Message Edited by hemmerling on 01-11-2007 09:19 AM

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Hello Hemmerling,

I think our threads got crossed.  I'm asking about timestamps be out of synchrtonization with cFP-2120 and cFP-AI-110.

Best wishes,


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Hi Hemmerling,

Those are a lot of questions, hard to answer over the forum! I would recommend to contact your local NI-Office and maybe to get a visit from a sales engineer to talk about the best solution for your specific application.

BR, Christian

Message Edited by Christian_M on 01-22-2007 10:14 AM

Message 5 of 6
Now after some days, there is ONE question left,
which cannot be answered easily by an NI office:

How much cFP-AI-112 or cFP-RTD-124
Samples / second
can I transfer by the serial RS-232 115.200 bps line ?

So how much protocol overhead is there on the serial line ?
Now with DEACTIVATED Filters, the cFP-AI-112 can do 10 KS/s,
and probably this cannot be transfered by RS-232,
especially if there are several modules,
but I would like to know HOW MUCH I can transfer.

Thanks in advance

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