Ladder Logic Problem

[DLD PE]

A good one to look at I think:

Here's one I got wrong and I actually started posting it because I couldn't figure out why.  I took this under simulated (timed) conditions.  This is an example of what happens when your brain isn't thinking clearly.

After re-examining the circuit, I figured out that it doesn't matter if or when the start button is pressed...the motor will operate as long as the temperature and pressure conditions are met and the timer is on.  The last thing I looked at to solve the problem was the graphs.  Then I circled my answer for choice C (10am and 2pm).

I got it wrong and I was thinking "HOW? I WAS SURE I GOT THIS CORRECT!"  Then I realized as I was posting this that I didn't go back and read the problem...the timer only allows the motor to run for 5 hours, so after 12pm the motor won't run no matter what.

 

[Flyer_PE]

I'm not a fan of the way they describe operation of the timer.  To me, the wording may lead someone to believe that it is a run-time limit for the motor rather than clock time from an outside initiating event.  Pressing the start button while the pressure is too low to permit a motor start is a nice touch.