USB-CTR08: High-speed counter/timer device with eight counter I/O

[Vasanthakumar]

Hi Team,

If it is possible to use counter input and pulse generation at the same time in the USB-CTR08 Module.

Please check the below-mentioned requirements spec meet in the USB-CTR08 Module.

1. Six Pulse Inputs( Open collector output, 0 to 5KHz, Duty Cycle 50%).

2. Four Pulse Inputs ( 5V, 20KHz, Duty Cycle 0 to 100%).

3. Sense the 2 PWM O/P with (5V, 25KHz, duty cycle 0 to 100%).

[JRys]

The USB-CTR08 has four timer outputs that can generate pulse signals. They are independent of the eight counter channels, each with an input, gate, and output. The counter inputs use a 47k ohm pull-down resistor. Add a 10k ohm pull-up resistor to the open collector signals. I'm not sure what you're asking about the other signals. Do you want to know if you can measure frequencies while outputting a PWM signal?

 

[Vasanthakumar]

Sorry for the confusion, I have rephrased my question below. Please review and share your feedback as soon as possible.

We have chosen USB-CTR08: High-speed counter/timer device with eight counter I/O for the below requirement.

https://digilent.com/shop/mcc-usb-ctr-series-high-speed-counter-timer-usb-devices/

Requirement 1: We have the requirement to generate 10 Pulses simultaneously.

Out of these 10 pulses,

• Four Pulses shall be 5V, 20KHz, Duty Cycle 0 to 100% --> Planned to utilize 4 independent timer channels to generate the pulses.
• Six Pulses shall be Open collector output, 0 to 5KHz, Duty Cycle 50% --> Planned to utilize 6 counter-output channels to generate the pulses.

Requirement 2: We have the requirement to measure the 2 PWM signals simultaneously (5V, 25KHz, duty cycle 0 to 100%).

• Planned to utilize 2 remaining counter-input channels to measure the PWM Signals.

Shall we meet this with the selected counter modules..? please confirm.

Regards,

Vasanth

[JRys]

The counter output can be enabled when using the Totalize mode, and range counting is typically used to count the same range repeatedly. The output can be set for an initial state, either high or low, and toggle to the opposite state when the count reaches a value. In this mode, you have a minimum and maximum range register and two output registers that dictate when the output gets set and reset. You will need a clock source so the counter input has something to count. You could repurpose one of the timers for this, but this would leave one short. You could consider using two USB-CTR04 instead; then, you would have eight timers to work with.

For precise duty cycle measurements, use the pulse width mode. It will use the internal timebase to count from leading to the falling edge of the input signal. It doesn't provide duty cycle percentage, instead you get a count whose time is determined by the timebase (ticksize) whose default value 20.83ns. Multiply the count by 20.83ns to get time. 

What do you plan for software? I recommend using the Universal Library API (Python, C, C#, VB.NET) because it provides better device control than programs like DAQami, DASYLab, and LabVIEW. 

[Vasanthakumar]

Dear JRys,

Thanks for your response. Here the counter output does not generate a pulse..?

One more requirement --> In this module (USB-2416-4AO and AI-EXP32) shall I measure 10 single-ended Analog Input and 5 Differential Analog Input simultaneously..?

Regards,

Vasanth

[JRys]

The USB-2416-4AO (and AI-EXP32) inputs can be individually set to either differential or single-ended. However, the device has only one A/D converter, which is shared among the channels. Because of this, the measurements are not truly simultaneous. For example, if the sample rate is 100 Hz, the gap from channel to channel is 10ms.