A PLC is used to control the sequence in an automatic drilling operation. A human operator loads and clamps a raw work part into a fixture on the drill press table and presses a start button to initiate the automatic cycle. The drill spindle turns on, feeds down into the part to a certain depth (the depth is determined by limit switch), and then retracts. The fixture then indexes to a second drilling position and the drill feed-and-retract is repeated. After the second drilling operation, the spindle turns off and the fixture moves back to the first position. The worker then unloads the finished part and loads another raw part. Let the input/output variables for this system operation be (X1, X2, C1, Y1, etc.). As a first step, construct the ladder logic diagram for the system and write

Question

the low level language statements for the system using the PLC instruction.

What will be an ideal response?

Answer 1

X1 = spindle up

X2 = spindle at desired depth

X3 = fixture at position 1

X4 = fixture at position 2

X5 = start button

Y1 = spindle on

Y2 = spindle down

Y3 = fixture to position 2

C1 = drill cycle permit

C2 = hole 1 drilled



LD X5

AND X1

AND X3

OR C1

LDI C3

ORI X1

ANB

OUT C1