rthh Posted March 1 Report Share Posted March 1 Hello I'm writing to you because I'm having a problem compiling my program on Visilogic. When I compile, I get an error such as: Illegal number of rising or falling edges. So I'd like to know if there's a trick or method to quickly identify where my error is. Thank you very much Good day Quote Link to comment Share on other sites More sharing options...
DanT Posted March 1 Report Share Posted March 1 Hi; There are limits to the number of -|P|- and -|N|- that can be used in a program - They also take up more processing time than a -| |- contact. Aslo Review the Help Topics Contacts Postive Transition Contact(Rise) for further information. If you have several -|P|- assigned to a single MB say MB11 - say you use it 6 times. then do this -|P|- -( )- MB11 turns on MB12 do this at the start of the ladder Now use -| |- MB12 in place of the MB11 -- does the same thing the leading edge pulse.( also saves scan processing time) Also Examine your program as to why you are using so many of the -|P|- and -|N|- in your program. You can also upload your program and some one can do a review and provide some suggestions to reduce them DanT Quote Link to comment Share on other sites More sharing options...
Gabriel Franco Posted March 1 Report Share Posted March 1 Verify that the total number of rise/fall bits used is not greater than allowed. Use View|rise/fall summary menu Quote Link to comment Share on other sites More sharing options...
MVP 2023 Flex727 Posted March 1 MVP 2023 Report Share Posted March 1 1 hour ago, DanT said: There are limits to the number of -|P|- and -|N|- that can be used in a program As Dan correctly points out, transition contacts are limited in your PLC program. The reason for this is that in order for the transition contact to work properly, memory must be set aside to "remember" the state of the bit operand on the previous scan. The size of the block of memory set aside for transition contacts varies by PLC model from 256 to 1024, but sometimes the actual compiled number of transition contacts is greater than what you can count in ladder due to the result of the STL translation from ladder that actually gets compiled. Quote Link to comment Share on other sites More sharing options...
rthh Posted March 4 Author Report Share Posted March 4 hello ok very well thank you all, I will try to be more frugal with the rising element . Thanks for your help Quote Link to comment Share on other sites More sharing options...
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