HW 8 chapter 8

Normally, when power to your PLC system is lost, when power is restored the counter accumulated value will be:

• zero

• whatever it was preset for

• maximum

• unchanged

The output of a PLC counter is switch from “off” to “on” any time the count input rung is "true".

• True

• False

A PLC up-counter normally counts true-to-false transitions.

• True

• False

In order for the PLC counter to reset, the counter reset rung must be “false”.

• True

• False

The done bit of a counter is true whenever:

• the accumulated value is equal to the preset value

• the counter instruction is true

• the accumulated value is greater than the preset value

• both a and c

Fill in the Blank: The---------value of a PLC counter is the current count based on the number of times the rung goes from false-to-true.

• preset

• overflow

• accumulated
• underflow

Count rung transitions can be caused by actuating: a. a limit switch b. a sensor c. a pressure switch d. any of these.

• limit switch

• sensor

• pressure switch

• any of these

The down-counter output instruction will increment by 1 each time the counted event occurs.

• True

• False

Normally the down-counter is used in conjunction with the up counter.

• True

• False

For the program shown, if the in-feed switch is pulsed 9 times followed immediately by 5 out-feed switch pulses, the accumulated count would be:

• 0

• 14

• 50

• 4