NI-DAQ USB-6343 (BNC) max current

[manuel.weibel@sonova.com]

Hi

I would like to drive a small valve with NI-DAQ USB-6343 (BNC). Drive current is 10-12mA.

When I set the AO the current limits to 9mA.

Datasheet says: Overdrive current 15 mA

Is there a limitation to that 9mA?

How can i increase the limit to 15mA?

I using MATLAB with Data Acquisition Toolbox to control the image.

Thanks, and regards

Manu

[_Bryan · Accepted solution]

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manuel.weibel@sonova.com wrote:

Hi

I would like to drive a small valve with NI-DAQ USB-6343 (BNC). Drive current is 10-12mA.

When I set the AO the current limits to 9mA.

Datasheet says: Overdrive current 15 mA

Is there a limitation to that 9mA?

How can i increase the limit to 15mA?

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Hey Manu,

You might want to take a look at the link below.

http://www.ni.com/product-documentation/53090/en/

According to the 6343 spec sheet: Analog Output current drive ±5 mA

From the link above under the section Output Current Drive:

For analog output, output current drive is the maximum amount of current that the device can sink or source. The load that is connected, including output impedance, combined with the voltage programmed determines the current that will be required to maintain programmed output voltage.

Programmed output voltage is guaranteed if current drive remains below the specified output current drive. Exceeding output current drive puts the device into an overdrive state, where output voltage is no longer guaranteed.

If you are getting 9 mA I would expect that your voltage is no longer at your setpoint.  You will probably need some type of amplifier to control the valve.

[manuel.weibel@sonova.com]

Hi Bryan

Yes, you are right, at 9mA Voltage is not at Set Point anymore.

The explanation in the Datasheet is not that clear about "Overdrive Current". With the "Specifications Explained: NI Multifunction I/O (MIO) DAQ" it makes sense.

With <5mA max output voltage is possible. With higher current, output voltage drops to 15mA at short circuit.

Thanks, Manu