10 volt digital output

[scoobydont]

Is it possible to increase the digital output from a PXI 6251 to 10 volts?

[Stuart_R]

The digital lines are TTL in nature and therefore operate at two logic levels 0V and 5V, you cannot change this. With extra hardware you could use the digital outputs to drive a relay or similar which in turn switches 10V. Could you explain to me what you are trying to achieve with this 10V?

Could you use the Analogue Output instead? This can output a 10V signal, but it will depend on what you are using it for.

Thanks,

Stuart

[scoobydont]

Thanks for replying Stuart.

I'm sending a bianry address of at least 10 volts on 6 address lines. This gives 64 addresses, 0 to 63. I need to send address voltages at 50KHz and although analogue worked for a simple trial we only have 2 ao ports on a 6251 card. We are trying an inline voltage amp between card and third party hardware.

again thanks for the answer.

Darren

[Buechsenschuetz]

If you need a 10V digital signal which is supposed to be rather fast a relay or opto-isolator would not be a good choice since they have rather slow response speed (in the order of milli-seconds).

The easiest way is to use an additional output npn transistor (almost any will work), with the base connected to the digital output via a resistor of, say, 10kOhms. Connect the collector to an external 10VDC source and the emitter to GND (GND of external source must be connected to digital GND of board). You will receive a digital signal with approx. 10V high level and 0.5V low level (equal to the c-e saturation voltage of the transistor). The logic state will be inverted.

To protect the board in case of transistor burn-out, connect a diode with the cathode to the base of the transistor and the anode towards the digital output in series with the base resistor. You can connect one more resistor of, say, 47kOhm to increase switch-off speed of the transistor directly from the base to GND.

[AnalogKid2DigitalMan]

Buechsenschuetz:

There are FAST optos out there- such as Agilent (HP) HPCL-2300 and related series, good in the MHz range.

Have a good one

-AK2DM

[scoobydont]

Thanks for your replies.

I the end 10volts was the minimum limit and we've had to increase to 15v.

We have used a single HEX level shifter chip which has 6 lines, ideal for our addressing, and two input, 5v from PCI 6251 TTL and 15v from external power source.

again many thanks

Darren