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Comparator in PLCopen, Change Cam on the fly

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Hi, I need to change a cam on the fly at a specific position and speed, in Pipe Network we have the comparator block to make the change, but is there a function to do the same in PLCopen?

Best regards




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The same ProfileBuild function block can be used with a PLCopen project. There is another sample project on KDN at that is done with PLCopen.


As for Comparator, can use the MC_ReadActPos function block to check when an axis is at a certain position to start or stop a cam profile. We also have a PLS function to check for a range of positions inside the Kollmorgen UDFB section of the function block library.


Thanks Joe, but if i use MC_ReadActPos or PLS function block its to slow, if slave is absoluted jumps and get significant jerk. i need to do this but with PLCOpen motion engine, I need to do the change in a specific position of the slave where the new profile has the same velocity and position when starts.

JUANPAVQ - Mon, 07/12/2021 - 15:13

Comparator in Pipenetwork is not anymore accurate than writing your own code in PLCopen, it still updates at the EtherCAT update rate. If you do not have an area of zero or constant velocity where it is easy to switch cam profiles, can have an overlapping area where the old and new cam profiles are identical and switch in this area. Would need to have master absolute option turned on.

Joe Parks - Tue, 07/13/2021 - 05:28

I get it, thanks Joe

JUANPAVQ - Tue, 08/31/2021 - 20:07
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Comperator blok is working is based on PLC cycle so you also can calculate proper point to change cam with using basic if statement (comparate acutal position).

But you have to careful when you switch profile to other. Your axis moment speed have to equal to new profile speed.


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