Page 299 - Programmable Logic Controllers, Fifth Edition - Mobile version

• LS2 turns on the soap release valve, which
mixes with the water input valve to provide a Station Station Station Station
1
4
3
2
wash spray.
• LS3 shuts off the soap valve, and the water input
valve remains on to rinse the vehicle. Reject Reject Reject
lamp
lamp
lamp
• LS4 shuts off the water input valve and activates status status status
the hot wax valve, if selected. Product
• LS5 shuts off the hot wax valve and starts the air-
blower motor.
• LS6 shuts off the air blower. The vehicle exits the
car wash.
Inspection zone Proximity Gate
7. A product moves continuously down an switch
assembly line that has four stations, as shown
in Figure 12-44.
• The product enters the inspection zone, where Figure 12-44 Assembly line program for Problem 7.
its presence is sensed by the proximity
switch.
• The inspector examines it and activates a reject • When a defective part reaches station 4, a diverter
button if the product fails inspection. gate is activated to direct that part to a reject bin.
• If the product is defective, reject status lights come • Using whatever PLC bit shift register you are most
on at stations 1, 2, and 3 to tell the assembler to familiar with, develop a program to implement this
ignore the part. process.

280 Chapter 12 Sequencer and Shift Register Instructions

pet73842_ch12_252-280.indd 280 03/11/15 7:20 PM