Multifunction DAQ topics

How to wire a Fluid Components International ST75 flow meter to DAQ System?

BBalmforth — Tue, 21 May 2013 18:48:30 GMT

Hello,

I'm trying to wire a ST75 flow meter to my DAQ system which consists of a PCI 6052E DAQ device, a SCXI 1102B card, and a SCXI 1300 terminal block. The 1102B has four 249 Ohm resistors connected to channels 0-3 for use with the current signals from the flow meter.

The flow meter has two 4-20 mA output signals, and RTN, SINK, SOURCE, and COM connections. The documentation isn't clear how to connect the sensor to the terminal block, other than saying if both output signals are used, one RTN lead is used. So far, I cannot get the flow meter signal to work in LabView, so I'm not sure if I have it wired correctly. Currently I have OUTPUT 1 wired to CH2 + on the terminal block, with CH2 - wired to the chassis ground terminal and to the COM lead on the sensor.

Thanks in advance.

McAfee causes DAQ misread

verdmonte — Tue, 21 May 2013 13:40:49 GMT

We have been running production s/w with Labview 8.6 for some time (4 years). We are using a PXI 6071E with Traditional DAQ drivers. Recently we discovered that during a long 5 minute DAQ read of an Analog Input we would get an incorrect read. There was no error recorded from the DAQ but you could see that intermittently the DAQ read would start showing pulses where a steady voltage should have been. This would be very intermittent maybe once out of 50 runs (we run 24/7). We are sampling at a very low rate of 20 samples per second. After many attempts at modifying the configuration of the DAQ we disabled McAfee and have not seen the problem in over two weeks. We suspect that due to the fact that the DAQ uses a very high CPU processing time and that McAfee can also hog the CPU periodically that when this happened that it interrupted the DAQ.

AO Spannung soll auf 0 wenn USB Verb. gekappt, wie Not-Halt

P3lzi — Tue, 21 May 2013 10:53:24 GMT

Hallo Community,

gibt es eine Sicherheitsfunktion die mir die Spannungsausgänge meines im cDAQ befindlichen AO Moduls auf 0 setzt sobald die USB Verbindung getrennt wurde?

Da an dem AO Modul ein Frequenzumrichter mit Motor hängt, dessen Drehzahl über die Spannung (0-10V) gesteuert wird, wäre dies eine wichtige Sicherheitseinrichtung.

Ich schätze mal Softwaremäßig ist das nicht zu regeln? Da ja sobald die Verbindung getrennt ist auch keine Befehle mehr weitergegeben werden können...

Thermocouple readings fluctuating JType

sonotk — Tue, 21 May 2013 00:42:24 GMT

When acquiring temperature using NI 9213 of J type thermocouplethe temperature readings are fluctuating. Attach is the screen shot of the temperature showing the fluctation. The actual temperature is between 123 to 125 deg C and it drops after an interval to around 63 deg C. The width of the drop is approximately the same.

Some options tried were

1. Connecting the negative terminal of thermocouple to chassis ground. This did not help and the temperature dropped to almost half.

2. Connecting the COM to chassis ground did not help either.

3. All the wires and connections were tested and when testing using handheld thremometer directly the readings does not fluctuate.

Any suggestions as what might be causing this?

TIA.

Class 1 TEDS acquirement.

jsoriano — Mon, 20 May 2013 15:37:53 GMT

Hello, I am an student doing my final project and trying to acquire the TEDS information of an accelerometer with SC-2350 but I cannot. I have thought the problem maybe was that SC-2350 only can acquire class 2 TEDS information. However, are there any posibility for doing this acquirement (class 1 TEDS) with SC-2350 (with previous conditioning)?

The university provide me just SC-2350, the SCC-ACC01 accelerometer input and an accelerometer with TEDS (class 1).

PS: I expect the post is in the correct forum.

Is is a proper way to solve the problem of high common-mode voltage?

xcuresme — Mon, 20 May 2013 13:24:28 GMT

Hi, guys~

I am now using PCI-6251 to sense the voltage Vsense in figure 1, whose amplitude ranges from -5mV to 75mV.

figure 1

As we can see when T2 and T3 are closed, the common –mode voltage of Vsense is as high as 160V!!! But the working voltage of PCI-6251 is only 11V.

So I plan to change the Vsense from a grounded signal to a floating signal. That means the DC voltage source of 160V is provided by an isolated AC/DC power supply as shown in figure 2. In this way the “ground” of the Vsense is different from the ground of DAQ.

Figure 2

Could anyone tell me whether this solution can work safety?

Thanks in advance for any assistance!

nidaqmx DIO high & low

aderogba — Mon, 20 May 2013 05:42:21 GMT

Please which nidaqmx function can ne used to set port state to high or low as show in the attached diagram?

NI cDAQ-9174 system.

uiet — Sun, 19 May 2013 18:57:58 GMT

Hi,

I have NI cDAQ-9174 system.I am using "NI 9205 with spring terminal" module for voltage measurement of signals from different sensors. But i want to take gps data also through this cDAQ so which module i required.

Changing Counter Input Terminals in NIDAQmx for PCI 6229

OptEng — Sun, 19 May 2013 18:57:17 GMT

I'm configuring two independent "Edge" counters on a PCI 6229 in ANSI C using the NIDAQmx 8.0.2 library. I've searched the KB and found the article on "Changing the Input Terminal (Source) for a Counter Measurement with NI-DAQmx", the function (DAQmxSetCI...Term) in the section at the bottom (ANSI C) needs an argument "channel[ ]". I'd like to use independent "aux" and "B" signals (four PFI lines total), but the pin connection is redundant (refer to the PCI 6229 hardware manual), so I'd like to know if the "Term Names" on the following page http://zone.ni.com/reference/en-XX/help/370466W-01/mxcncpts/termnames/ are to be used to specify the channel to move the signals so each has its own input pin. If not, what do I use?

Thanks in Advance,

OptEng

What is input equivalent circuit of USB 6009 PFI0

kscholl — Sun, 19 May 2013 09:55:19 GMT

Is the USB 6009 PFI0 input the same as the analog circuit input shown in the user manual?

I am using the PFI0 to trigger a voltage measurement and it works great using an HP function generator.

When I try to drive the input low with my circuit it looks like there is a pull up resistor to +5 on the PFI0 input terminal.
Will this PFI0 input accept a 0 to 15 volt comparitor output with being damaged?

Kip

voltage reading at DAQ board is not same with the voltage input supplied

syedanas — Sun, 19 May 2013 00:32:34 GMT

hi guys,

i am doing this project.the project is as the figure in the attachment below.

im trying to create a simple GUI which will display the voltage input at analog pin a0 and a1.my question is;

1)why is the voltage input supplied to the DAQ is different when it display at the the front panel compare with the one i measured with a multimeter.the gap in the reading is huge.

2)i am using index array to separate the voltage from a0 and a1 in a single task,is that applicable?

3)if i want to display the reading of the voltage input at different point of frequency range 1-3 Ghz ( sweep frequency),how should i do that.there is already a RF generator connected to the device,so do i need to make a sweep frequency VI also in the labview?

the vi is at the attachment.

PCI 6110

dev_digilogic — Sat, 18 May 2013 05:09:59 GMT

Hello everyone, I have PCI 6110 DAQ card which has a maximum source frequency of 20MHz,I am generating a frquency using MAX.when i generate more than 5MHz.I m getting error which indicates that the desired generated frequency is out of range? can anybody explain what is the reason.

How to change analog output rising edge and falling edge.

Zhi — Fri, 17 May 2013 16:50:28 GMT

Hello guys. I am a beginner of a USB-6259 DAQ board. I am wondering can the rising and falling edges be adjusted through programming (changing the slope)? I did not see any related instructions in the manual. If anyone has any clue, please inform me... Thanks.

1MS/s/ch Simulltaneously sampled, Single Ended Analogue Voltage measuremnt DAQ

sm81 — Fri, 17 May 2013 14:41:43 GMT

Hello there, I have been looking up your products for something I need for my work. I have been looking for simultaneously sampled (1MS/s/ch) analogue channels for 'Single Ended' measurements. I can't find any DAQ (USB/PXI/PXie) which can do this. I have PXie-6124(4MS/s/ch, 0 SE, 4 DI), which according to one of your colleagues, can't do SE because it doesn't support RSE/NRSE. I am currently using PXI-6251 (1.25MS/s, non simultaneously sampled) which is fine as long as I use 2 or less channels (I can divide the sampling rate by 2 and still good) and I can do both SE and DI. But, I can't find a DAQ which is both simultaneously sampled and allows SE. Any reason why I can't/ shouldn't do this? Thanks.

cRIO

Rez8 — Fri, 17 May 2013 13:13:48 GMT

Hi,

I went to run a rather important test yesterday and had issues communicating with the compact rio, I checked the status LED and it is flashing twice every few seconds which according to the manual means:

2 The controller has detected an error in its software. This usually occurs

when an attempt to upgrade the software is interrupted. Reinstall

software on the controller.

Now is it possible to just reinstall the controller software without having any sort of adverse effect on any of the labview code that has been set up? Myself and my supervisor are concerned that should we make an attempt to put the controller software back onto the crio it will mean that we lose communications alltogether (currently within MAX it shows that it is connected but software is missing).

How would this have happened in the first place? there would have been no attmept to upgrade the software in the first place.

Thank you in advance

Reza

my daq

sfstolf — Fri, 17 May 2013 03:32:27 GMT

Hi all. Anyone knows if there is any way to create a lock-in amplifier vi that utilizes the MyDAQ device?

Can I drive a stepper motor via DAQPad6020E??

REZA1360 — Thu, 16 May 2013 22:53:08 GMT

Hello,

I have an old stepper mote (Compuotomotor ) which has driver (Indexer 2100). It aslo should be possible to control it through an RS232C (DB 25) serial port. I was wondering how can I connect my DAQPad6020E to this 25 pin RS232C port and control the stepper motor by using my Labview.

I attached the manual of the indexer to this email.

THANKS!!!!

REZA

pci-6731 error -50400

MSinghUH — Thu, 16 May 2013 20:48:23 GMT

I am using a PCI-6731 in a Windows 7 64 bit computer. When I run the VI for controlling a mirror galvanometer for an OCT system, it throws an error code of -50400 from the DAQmx start task vi. The card is visible in MAX, I have reset the device in MAX, uninstalled it in device manager and reinstalled it. I have also repaired DAQmx and LabView from uninstall/repair/modify from the control panel. The problem is that the card works in another system which runs the same OS and version of LabView and it worked yesterday in the system in which it is not working today. The card passes the self-test in MAX too. I'm out of ideas.

LabView version 2010 64 bit

DAQmx version 9.7

Fast acquisition rates cause delay when viewing data on a graph

OKors — Thu, 16 May 2013 19:48:39 GMT

I'm using a cDAQ 9172 and 9215 AI module connected to a laptop running Signal Express, Core2 intel, Win 7, 4Gb Ram.

For my testing needs I rely heavily on being able to watch the data in realtime on the graphical display (chart graph, or xy).

My problem is, If I sample high enough to avoid aliasing (100Hz/10samples to read) the plot becomes heavily delayed by up to a few seconds. I'll put an input into the test rig and the graph will display that change in signal several seconds later. This is unusable for me. The only way I can view the data on the graph in realtime is to reduce my sample rate but then I'm left with horrible resolution.

Is this a throughput issue with the USB or timing related? I've tried various timing settings and nothing seems to land me in that sweet spot where I can view the data on the graph in realtime while maintaining higher sample rates.

How to run 3 sepearte VIs all using the same CompDaq (NI-9174, NI-9205, NI-9213)

ds110 — Thu, 16 May 2013 19:01:19 GMT

I would like to acquire data from 3 different test rigs using a single CompactDaq system which consists of NI-9174 (4 module chasis) , NI-9205 (16bit AI 0-10V), NI-9213 (16 ch thermcouple module). Each test rig will consist of 4 voltage inputs (0-10V) and two thermocpuple inputs). I want to be able to start and stop each VI as needed and log data at rate varying bertween every second to every 30 secs. I have tried hardware timed and software timed VI, and either get Error 50103 or 200284. Can this be done? Thanks. Dave