Gain Control for NI 4462 and knowing when a signal is over the specified Voltage input values.

[d1sturbanc3]

I have a NI 4462 hooked up and reading data. The spec sheet states that the board has the ability: "A programmable gain amplifier stage on the inputs gives gain selection from -20 to +30 dB in 10 dB steps." I looked for sample VIs that describes how to control the gain. But so far, I can't find any.

Also, is there a way to know if the input voltage value is greater than the specified min/max values to the DAQms create channel VI? Is it an error code?
Help? Thanks!


Message Edited by d1sturbanc3 on 02-05-2008 03:34 PM

[mallorim]

Hello,

You can program the 4462’s gain using a DAQmx Channel Property Node. The steps for selecting the property can be seen in the attached screenshot. You will want to place down the property node, which can be found on the Functions Palette>> Measurement I/O>> DAQmx>> Channel Node. You can then click on the property and select Analog Input>> General Properties>> Advanced>> Gain>> Gain Value. You can then right click and select “Change all to Write” to make this a control.

Just trying an example voltage program where I was reading a 0-5 V signal with the Maximum voltage set to 3 V did not return any error messages. I will search to see if there is any way to do this and post back if I find anything.

Regards, Mallori M.

Message Edited by mallorim on 02-07-2008 01:32 PM

[d1sturbanc3]

Thanks... works great..



Message Edited by d1sturbanc3 on 02-07-2008 02:49 PM

[d1sturbanc3]

In the manuel it states ""You can programmatically poll the overload detection circuitry on a per channel basis to monitor for an overload condition." in the analog input section. Anyone know where I can find this value to poll? Thanks.

[mallorim]

Hi d1sturbanc3,

You can programmatically poll the overload detection circuitry using a DAQmx Read Property Node. You can use the properties Overload Channels Exists, which outputs a true Boolean if an overload occurs, and Overload Channels, which outputs a string indicating the affected channels. You will want to place down the property node, which can be found on the Functions Palette>> Measurement I/O>> DAQmx>> Read Node. You can then click on the property and select Status>> Overload>> And then either property. Both of these properties will need indicators.

Regards, Mallori M.

Message Edited by mallorim on 02-11-2008 05:45 PM

[d1sturbanc3]

I'm having problem detecting overload in my setup. It's described in this thread. http://forums.ni.com/ni/board/message?board.id=40&message.id=6052&jump=true#M6052