Features
• Timed sequence control
• Interrupt device control
• Easy to understand process
• Low cost

Curriculum Coverage
• Fundamentals of Logic
• Basics of PLC programming
• Developing Ladder Logic Programs
• Programming timers
• Time based process control
• Programming counters
• Use of interrupts

This simple sequence application allows traffic light control of a cross-roads to be implemented on a timed sequence basis. The control program can be further developed to cope with interrupts gener- ated from pedestrian crossing requests or off-peak vehicle detector inputs.

The units use 5V TTL signals and can be interfaced to a PLC using standard 24V dc logical inputs. A PLC interface is required to operate the above units (34-403).