Programming instructions

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The HOUR instruction is a built-in hour meter. The function times the number of
seconds the function has been active. It allows the operator to set a value for the
number of hours which will turn on the output indicated in the final parameter.
It is recommended that the addresses used to store the current value in hours
and seconds should be in the retentive range in the PLC so they are not lost
when the PLC is powered off or reset. Timing will continue until the maximum
number is reached in the data register. This function can be coded as DHOUR
to use 32-bit registers and store longer time frames.
12.5 EXERCISE Timers and Counters
Please find Project #2 in the appendix. This project is intended to give the
student exposure to entering timers and counters, as well as exposure to
timer/counter behavior.
12.6 EXERCISE Conveyor Control
Write a program that uses:
X10 as the Start button (momentary contact)
X11 as the Stop button (momentary contact)
M0 is the latch contact (remain on for entire cycle, shut off after last conveyor off)
When the start button is pushed, turn on outputs Y0 to Y7 in sequential order.
These outputs are 8 conveyors that must be turned on in order. Each conveyor
comes on 1 second after the previous conveyor comes on. When all conveyors
have been running for 5 seconds, turn the conveyors off, in the reverse that they
were turned on, one at a time, one second apart.