Interfacing LabView compatible DAQ board w/ third party DAQ boards

[SPlamp]

Dear NI-team and board-members,

In my current project I'm using a third party Direct Digital Controller which supports customizable Programmable Logic Control (PLC) via a graphical programming software. Therefore, I'm acquisitioning temperatures (etc.) from my miniature-HVAC application via physically attached and mounted sensors, connect them to a dedictaed analog input (0-10VDC typically) and in further assign the analog input to some selected PLC modules with the help of the graphical programming software, and finally after doing the computation (calculator block) or control (Proportional-Integral-Derivative block) I assign the resulting control signal to a dedicated analog output (typically 0-10VDC as well).

So far for the previous history, NOW I actually want to be able, to manipulate these analog values in a way, that I'm not interested in the physical acquisitioned value from my real-time operating equipment (e.g. temperature sensors), more than that, I'm interested in assigning a certain level (e.g. +5 VDC) to that dedicated analog input, which in turn would represent a temperature e.g. in this simple case (+5VDC) 50degF.

Now to the questions, can I possibly interface the physical ANALOG INPUT (0-10VDC) of my third party DDC unit, with the ANALOG OUTPUTS (0-10VDC) of a NI DAQ board? In that way, I'd be able and with some additional help of LabView to program time intervals, where I raise the voltage level every 5 minutes by 1VDC, and in turn can proceed with my intended purpose.

To sum that up, are there physical limitations (e.g. ground loops, damage equipment, shorting) connecting an analog output of one board, to the analog input of another board?

Also, which DAQ of NI might be best suited for my intended purpose, using a NI DAQ board for "simulating" temperature values (etc.) onto the analog inputs of another third party board.

Thank you,

Sandro

[Salvador_Santolucito]

Hi Sandro,

If both boards are in the same computer I wouldn't be too worried about ground loops or damaging equipment. The ground reference to the AO board will be the same ground reference as the computer and AI board. You would have to check with the specs for your third party AI board to see what overvoltage protection it has and whether or not our AO board could give a voltage high enough to damage it.

I would suggest one of our AO boards to do the job. Depending on what kind of control and precision you want, we have static update boards available in PCI form. The static board will be cheaper but you are limited to software timed voltage updates (instead of clocked buffered waveform output).

http://sine.ni.com/apps/we/nioc.vp?cid=12550〈=US

I would suggest the AO board (PCI-67xx) instead of our M series multifunction boards because the AO boards have 8 or more output channels. The multifunction boards only have two output channels.

-Sal