Can I change the power on state of the USB-6501?

[xiphophile]

I just purchased the USB-6501, and every time it powers on all the lines default to inputs. I'm using this device as an output device to control  relays, and this creates problems. If anyone knows how I can change it please help. Thank you.

[Marni]

Hello Xiphophile,

You can set the direction of the digital lines of the USB-6501. To check to see if its possible look in the specs under Digital IO>>Direction Control. If its programmable the Direction Control will be "Input or output, software-selectable."

Setting power-up states in MAX:

1. Open MAX.
2. Under Devices and Interfaces >> NI-DAQmx Devices, right-click on your device and select Properties.
3. Modify the power-up state.
4. Click OK to write the settings to the device.

Setting power-up states in LabVIEW:

1. Place the NI-DAQmx Set Power-Up States VI on the block diagram.
2. Set the inputs "device in" and "power up states"
3. Add additional VIs to perform any other tasks within your program.
4. Run the program to write the settings to the device.

Please let me know if you have any questions. Have a great day!

Sincerely,

Marni S.

[MicrowaveDave]

Hey,

To further add to Mari's answer, the power-up state of the USB-6501 is always a high impedance input.  Each input is tied to a weak pull-up resistor and the DAQ  board does not drive it either signal high or low.  If it is necessary to set the power-up state of a digital line, other DIO boards do support that option.  For example, the power-up state of the PCI-6503 and USB-6709 can be set in MAX.  For future reference, the data sheet list usually lists what power-up states are available for a specific board.

David Hall

Applications Engineer

National Instruments

[trujillo66]

Hello all,

I have the same problem, but,

when I execute MAX, the "properties option" is disabled.

Devices and Interfaces / NI-DAQmx Devices / NI USB-6501: "Dev1" >> Properties (disabled)

?

Sincerely,

Domingo Trujillo

[Hal_L]

Hi Domingo,

As David said, the power-up state of the USB-6501 is always high impedance. This means that the digital lines are not driven high or low. Also, the properties option is MAX is always disabled for this device. National Instruments makes other hardware with programmable power up states if you need this functionality.

Regards,
Hal L.

[elven]

can i set the USB 6501 to high impedance mode in the labview software??

if can, can teach me how to set??

i nid to change the pin in the USB 6501 from input or output to high impedance mode??

[McKala[DE]]

The DAQmx channel property node includes the Digital Output tristate property.  This property stops driving a line and sets the output to high-impedance.  You must committ the task for the setting to take effect and this property can not be set when a task is running. 

The Digital Input tristate property causes NI-DAQmx to tristates the lines in the channel. If you set this property to FALSE, NI-DAQmx does not modify the configuration of the lines even if the lines were previously tristated. Set this property to FALSE to read lines in other tasks or to read output-only lines.

Good luck!

[jhy]

I understand that the power-on state of USB-6501 is in "high-impedance input" mode; however, I'm measuring 0V on some of the ports (without anything connected) when it is just powered on.  Does anyone know what might cause this??  My understanding is that measured voltages should be close to rail when it's in "high-impedance input" mode.

[McKala[DE]]

Hello jhy,

In Hal's post, he said "As David said, the power-up state of the USB-6501 is always high impedance. This means that the digital lines are not driven high or low."
When a line is not driven, it is floating and the measured voltage is not known. 

Regards,

[Rando]

How to set the power on state to Low ? I used as read port.

YC Heng