Ladder Logic Development

1
Ladder Logic Development

• Sawmill Reversing Motor Example

2
1. Sketch the Process
Limit Switch 1
Limit Switch 2
Forward
Reverse
Start Stop
3
List Inputs and Outputs

• Inputs
• Limit Switch 1
• Limit Switch 2
• Start Button
• Stop Button

• Outputs
• Master Control Relay
• Forward Relay
• Reverse Relay

4
Draw Rails and Rungs(One Rung per Output)
stop
L1
L2
MCR
FWD
REV
5
Draw MCR Logic
stop
start
L1
L2
MCR
MCR
FWD
MCR
REV
MCR
6
Add Controls