Call Function

Can anybody explain to me how the 'Call' function works in GE Fanuc Series 90-30???

I have to program a traffic light intersection and I was told to use the 'Call' Function in the _Main - LD

So i have to have subroutines of the Inputs, Outputs, Events, etc but I dont understand how the call function puts it all together. the help feature in the program doesnt explain it too well.

thanks in advance

also, in my subroutine ladders, why isnt the timers not working as it would in the main LD???

Your sub timers are not working because the sub has not been called form the main program. Sub-routine logic is not scanned unless the sub routine is "active".

Can't help you with the "CALL" function. I "assume" that is "calling" the subroutines.

Basically, you place the Call instruction in your ladder with the name of the subroutine. When the scan reaches the Call, it passes control to the subroutine and executes it. When the subroutine is finished, control returns. If you don't use call, there is no way for the PLC to know you want to execute a subroutine.

You can find more information at http://support.gefanuc.com. I would not search for Call as you will get all kinds of results.

They should look like this, kinda(using Proficy Machine Edition)

http://img693.imageshack.us/i/logic.png/

http://img134.imageshack.us/i/callblocks.png/