incorrect voltage reading

[willist2]

I'm using a DAQ6008 to measure an analogue input, a digital input and send a digital ouput.I have two questions:-

1, The analogue input reads between  -1.4V and 0.2V when 5V is applied to the board. I have mesured across the terminals and get approx 4.5V, which seems correct. This happens on the test panel and in LabView.Any ideas?

2, The digital output works fine, but i need to set the lines to ouputs through the test panel before i can send information. Is there any way of initialising the lines as outputs without running the test panel first?

thanks a lot in advance, Tom

[devchander]

for your Query 1, How have u connected signal to AI channel? in Differential or single ended mode?? coz you might have connected for singleended mode and be measuring in differential mode in testpanel/ LaVIEW or vise versa. check this out

Regarding  query 2, I do not think it is possible to change a default state of DIO lines of a board.

[willist2]

i was measuring in differential and the only other option was RSE. do you know what this stands for? I switched to this and am now reading between 0 and 2V which corresponds with my multimeter readings. Thanks a lot for your help.

[SachaE]

Hi,

  differential measurements are taken between two input channels (on the 6008 this would be AI0 and AI4 for AI0 in differential mode, AI1 and AI5 for AI1 etc)

 RSE is referenced single ended which is a measurement referenced to the AIGND pin.

For more information on the different measurement systems, and field wiring help, please see the following link.

http://digital.ni.com/public.nsf/allkb/c8156250190a1386862568b000753174

Hope that helps

Sacha Emery
National Instruments (UK)

[devchander]

Good to hear that it works,

as I can see, sancha has already answered that query with clarity

All the best, willist2

[TCPlomp]

Hi Tom,

I'm not sure what you'r meaning with setting the ports to output. You can do this with LabVIEW and DAQmx. And I know that you can even set the power-up state for some boards i'm not sure how this is done with the 6008. As a good start you should look at the LabVIEW shipping example for digital output. Be aware that you cannot control every board with a clock for the digital output and you might have to rely on software timing.

Ton

[CarlosOtiniano]

This document will be able to read analog signals from a DAQ USB6008, this program is useful to read the value recorded by a temperature sensor

https://decibel.ni.com/content/docs/DOC-31783