I disagree on timer and out of box thinking.raydog26
I am with kamenges on this one. I think your assignment is great. Reading the last sentence of the description of your project I'm pretty sure you need to engineer a timer. Otherwise you would be able to wedge button one down, then place one hand in the machine while pressing the button 2 with the other.
I have'nt done much programming for RSLogix but some other brands have special internal bits or relays that work off the clock of the cpu (S:4 Free Running Clock).
This is only my opnion but the professor maybe teaching the students to read, research, ask questions and think outside the box on this one.
Tom
!raydog26 said:I think the man reason for this exercise is to show the importance of writing a code that is safe for the operator because if it is wrong injury and/or death can occur.
yes you are correct. he told us in class no timers. he used to give this assignment for a grade but to many students got frustrated and quit because they couldn't figure it out so now it is extra credit assignment.
I was thinking of writing one like that using six or seven cascading bits to act as scan counters to meet the test requirements and actually have one capable of working with a real human and two separate buttons (if the PLC is slow enough, a few scans tolerance on button press timing might get us close to 100ms).Is it possible the professor is looking for series of b3 outputs going upwards to use the plc scan time as a timer - he did say you can use as many b3 coils as you like.
Paul