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Topic-icon Interferences in pulse inputs FBL2360

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2 months 1 week ago #29534588 by acevedo_05

Hello,
I am having some kind of trouble with my FBL2360. I'm sending PWM from a PLC to the pulse inputs of two controllers, and I am also using a digital input for the safe stop. The thing is that after a safe stop, sometimes, the controllers go a bit mad and some wheels move when I am sending a PWM from PLC that corresponds to a 0 motor command. I've monitored the signals with the application and I see that the controller is receiving the comand of 0 and max speed intermitently, even when my PLC is only sending the 0 command. I don't know if you could have any idea of why this is happenning or anything I could do to solve it.
Thanks for your time

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2 months 1 week ago #29534593 by Gabriel_Isko

I am not exactly sure what is going on, but we should check for 2 things:

1) Please make sure that the controllers remains in pulse input mode and that you aren't sending serial command from a script somewhere.

2) please verify that there is no noise on the pulse input command, or that your PLC isn't sending it some signal somewhere. You may have to capture the input with an oscilloscope to verify this.

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1 month 1 week ago #29534629 by acevedo_05

Sorry for the delay, and thanks for the replay, I have had no time for checkin these things until today.
The controllers remain in pulse input mode, so this may not be the error.
Concerning the second advice, I'll try tu capture the output of my PLC with an oscilloscope next week. For now what I've seen is that not every input has this 'noise'. I am using DI7, DI1 and DI4. DI7 and DI1 to capture pulse, and DI4 for safety stop.
DI1 and DI4 are close in the DB25, and I've seen that DI1 is the output which usually has this noise (in both controllers)
I've also changed the wires from my PLC to the controllers, using ones with shield.
However, I will try to make more tests next week and try to give more information.
Thanks for your advices, I hope to share new results next week.

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1 month 1 week ago #29534632 by acevedo_05

Hello,
I wanted to add that I am using the duty cycle as the capture mode, and I am sending a PWM with frequency of 250Hz. I have seen in the manual that this is the limit frequency, so should I change this frequency to a slower one (200 Hz for example)?

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1 month 1 week ago #29534636 by acevedo_05

Hi,
Updates from these couple of days:
I've seen that these interferences are seen in only one of the two channels of my controllers (at least for now) and they are not within the min or max range of input i have defined. By the way I can not set the command safety of the pulse input to keep it within the min/max range because the controller seems to not save this change when I do it, and I don't know why.
I don't know if this could be a possible solution, I am also thinking on put some actions on min and max (for example a safe stop) because this occurs after a release of a safe stop, but when another safe stop occurs and release, the interferences seem to disappear.
I am kind of lost with this problem as I can't really understand what is happening
Some help would be great

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