Send a fast TTL pulse

5 posts / 0 new

Thu, 05/03/2018 - 02:14

fish

Hi,

I am wondering about sending signals using LJPython, how can I send a TTL pulse with a rate of 300 Hz, and amplitude of around 5V? Thanks for your help!

Thu, 05/03/2018 - 15:14

LabJack Support

You can do so by toggling

You can do so by toggling digital outputs. They use 3.3 V logic. 5 V outputs are discussed in the digital I/O section of the datasheet:

https://labjack.com/support/datasheets/u3/hardware-description/dio

Regarding LabJackPython, our quickstart demonstrates setting digital I/O:

https://labjack.com/support/software/examples/ud/labjackpython/low-level

You can control pulse timing with software delays (time.sleep), or perform one getFeedback call with three or four commands to set the digital output high (u3.BitStateWrite), hardware delay (u3.WaitShort and/or u3.WaitLong), and set digital output low (u3.BitStateWrite).

Thu, 05/03/2018 - 23:37

fish

Got it. Thank you!

Mon, 11/15/2021 - 11:34

Wally

Hi there,

I am struggling with the following (similar) problem and I am not really sure where to start.

I would really appreciate your help.

I'd like to send a TTL pulse (+5V or -5V) to run a device.

I have a Macbook connected to Labjack U3 using USB which I plan to connect with the targeted device using a BNC connection (on the device side) and FIO4/GND sockets.

My questions:

1. Which command would be the best to send the TTL pulse? Can you provide me with an example?

2. Does the TTL pulse should have some temporal parameters?

Thanks

Mon, 11/15/2021 - 14:07

LabJack Support

Please note that the DIO use

Please note that the DIO use 3.3V logic and you will likely need some external logic shifting if you need 5V output. Some options are described in the following section:

https://labjack.com/support/datasheets/u3/hardware-description/dio#5Volt...

If you need to send a single short pulse, the easiest option should be to toggle the DIO manually as previously described in this thread. If you need a continuous pulse output or a variable number of pulses you could use our timer/counter features: the PWM output timer feature to generate the pulses, with a timer set up to use the timer stop mode if you want to stop after a certain number of pulses. Our timer/counter documentation has additional information:

https://labjack.com/support/datasheets/u3/hardware-description/timers-co...

What OS and programming language do you intend do use? Our software recommendations and examples could depend greatly upon these.
I do not understand the question; could you please elaborate?