How to Detect Pulse Presence? Pulse Catch?

[EkremVK]

Hi all!

I need help with detecting the presence of a pulse signal on an input.

I have a İQ-F FX5U PLC, and a sensor generating a pulse signal with 500 Hz frequency. When the sensor detects nothing, it outputs just flat 0 volts. But if it detects something, it outputs a 500 Hz pulse signal with a varying duty cycle (the duty cycle depends on the condition of detection but that is not relevant, I don't need that). I only need to detect whether there is a pulse signal on the input or there is just nothing.

I thought of using Pulse Catch Function which I've never used before, but I couldn't comprehend how it exactly works. Looking at the image below; since there will be always a pulse signal on the input when the sensor detects something, "Input Device" will always be ON. And when the sensor detects nothing, there will be no pulse signal on the input, so the "Input Device" will be OFF. But what is that Input Device exactly? Is it a relay? An output? Or is it the result of an instruction (which I've found nothing as such)?

So, if anyone can help me with this Pulse Catch Function or another solution, I would be glad.

Edited November 1, 2019 by EkremVK
Adding additional information

[EkremVK]

Anyone? I still couldn't figure out, nor the technical support.

[arturm@sperryrail.com]

hi.

I think you can use SPD command. [SPD  X0 K100 D5]   counts inputs in X0  during 100ms and put in to data register D5.

After that you can use [> d5 k20]  . If data register d5 is greater then 20 you can switch some device on . Im using gx3 for programming. and that code works for fx5uc.

 

[Inntele]

LD X0
OUT M0
[END]

where M0 is a desired signal of presence the pulse sequence at X0 input

 

[EkremVK]

On 07.11.2019 at 4:28 PM, arturm@sperryrail.com said:

hi.

I think you can use SPD command. [SPD  X0 K100 D5]   counts inputs in X0  during 100ms and put in to data register D5.

After that you can use [> d5 k20]  . If data register d5 is greater then 20 you can switch some device on . Im using gx3 for programming. and that code works for fx5uc.

 

Thank you very much. It works just fine