15. Handy Instruction Design Examples 15.1 ALT - Auto Blackboard Cleaner (Left side limit switch) X1 (Right side limit switch) X2 X0(Clean) Control Purpose: z Controlling the auto cleaner to move left / move right when Clean is pressed. z When the auto cleaner touches the limit switches of left side or right side, the cleaner will stop. Next time when Clean is pressed again, the cleaner will move to the opposite direction. Devices: Control Program: X0 M0 X1 Y0 Move left M0 X2 Y1 Move right Program Description: z When Clean is pressed, X0 will be activated one time to execute ALT instruction. M0 will be ON, the cleaner will move left until it touches the left side limit switch.
X1 = ON, and Y0 will DVP-PLC Application Examples 15-1 Y0 Y1 Move Left Move right Y0 Move Left Y1 Move right Y0 Move Left Device Function X0 X0 = ON when Clean is pressed. X1 X1 = ON when left side limit switch is touched. X2 X2 = ON when right side limit switch is touched. Y0 Move left Y1 Move right ALT M0