How to setup USB 6009 default level

[青风细雨楼]

I want to use NI USB 6009 digital port  to control an external relay, but when i turn on the computer or connect this device with computer, the digital port will be high level and the external relay will on.

How can I setup the default value of digital port to low level when i turn on my computer or connect the card to my computer? 

[johnsold]

From the USB-6008-9 User Guide: "At system startup and reset, the hardware sets all DIO lines to
high-impedance inputs. The DAQ device does not drive the signal high or
low. Each line has a weak pull-up resistor connected to it." Page 18.

On page 17 it shows and the specifications on page 21 list a 4700 ohm resistor to +5 V.

Is this enough to turn on your relay?

The USB 6009 does not have the capability to program startup modes. Some of the more expensive devices do have this capability.

Lynn

[青风细雨楼]

OH, my god.

How can i do then?

change another card?

[johnsold]

Computer problems. I have not been able to get to the Forum.

Some boards do have programmable power on states. I do not know from memory which ones those are.

Other things you might try: Configure your relay so that the line must be pulled to ground to energize the relay. connect the positive end of the coil to +5 volts and the negative end to the Digital Out.

OR add a transistor inverter between the Digital Out and the coil. Configure the circuit so that the internal pull up of the 6009 keeps the transistor off so the relay is off.

Lynn