S7-1200

[goner]

Hi, I have a application, where is 100 different products. Operator chooses the correct program from the push wheel ( http://uk.farnell.com/te-connectivity-alcoswitch/dps9131ak/switch-digital-push-wheel-bcd/dp/1701060) . PLC reads the code and activates according to the number on the push wheel a memory bit e.g. M60.0 . When the operator changes the program from the push wheel , the I need to reset the machine and reset some memories. I found a easy solution for it. I made added an OR instruction, with 100 inputs. In every input is a positive edge instruction. One for every product. So I have 100 positive edge instructions here. M60.0 - M69.7 M100.0 - M102.3 Is there a way to make this big OR instruction shorter or replace with some special function?

[Crossbow]

If they are dialing in a number in BCD, can't you just do a compare in the program to see what number was dialed in? When you start a product, store the number to a register. Then when the number on the wheels doesn't match the stored number, do your resets and preparation for the next number and then overwrite the saved number.

[Moggie]

You could write your own function to check for a BIT turning on - Edge evaluation, rising, word by word L MW 150 //Load old input value (edge memory bit) L MW 60 //Load input value T MW 150 //Transfer current input value into old value (edge memory bit) XOW //Link old value and input value using "EXCLUSIVE OR" L MW 60 //Load input value AW //Link result with input value using "AND" T MW 102 //Transfer result to "rising" pulse memory word L 0 <>I = M 0.1 M0.1 will be "HIGH" for one program scan every time a bit goes HIGH in the word MW 60. Just repeat the code for every MW you want to check. This was written for an S7 300; STL/IL is not supported in the 1200 but should convert easily. Use of a MD will check for 32bits at a time instead of 16bits at a time with MW Edited March 11, 2012 by Moggie