High active pull down trigger

[minni]

Hi everybody,

I need to make a LabView programmable trigger via TTL signal. The TTL signal should by default be high-active 1 kOhm pull down. When not switched on, the trigger input must be held at 5V, using a 1 kOhm resistance.

I have already a NI USB-6501 device, but if I understand well, this cannot be used for this purpose, can it? What else could I use? Would a NI USB-6509 do?

Many thanks.

[crossrulz]

I'm not sure what you are asking for.  But it sounds like you just need to tell DAQmx to invert your line and use a series 1kOhm resistor.

[minni]

Hi crossrulz,

I'll try to be clearer. What I meant was: I need to trigger a device.

- To keep the device inactive one of its inputs must be held at 5V,

- To swtich it on, I need to pull this input down to 0V.

Can I use a single output line of the NI USB 6501 to do this?

Thanks again.

[crossrulz]

---

@minni wrote:

Hi crossrulz,

I'll try to be clearer. What I meant was: I need to trigger a device.

- To keep the device inactive one of its inputs must be held at 5V,

- To swtich it on, I need to pull this input down to 0V.

Can I use a single output line of the NI USB 6501 to do this?

Thanks again.

---

Yes you can.  A digital output will drive 5V or sink down to 0V.