Simple Latch Circuit in Siemens TIA Portal V16

 Simple Latch Circuit in Siemens TIA Portal V16

Step 1: Configuring the PLC Hardware in TIA Portal

• Open your project in TIA Portal and access the Project View.
• Your configured PLC appears here.
• To add more hardware slots/modules, click the slot addition option in the project view and select your module. It will appear attached to your PLC overview.
• Enlarge the PLC view to 400% for better visibility of inputs, outputs, and the LAN interface.

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Step 2: Setting IP Addresses for Network Communication

• Double-click the LAN interface in your PLC project to see its IP address.
• Check your computer’s Ethernet LAN card IP address via network settings.
• Example: PLC IP = 192.168.0.1; PC LAN card IP = 192.168.0.2
• Ensure your PC IP address is either greater or lesser than the PLC’s to maintain proper networking basics.
• This setup enables communication between your PLC and PC over Ethernet.

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Step 3: Writing PLC Program Logic (Ladder Logic)

• Navigate to the PLC program block section and open the main organization block (OB1) by double-clicking it.
• The ladder programming window opens, where you write your code.
• Basic elements needed:
• NO (Normally Open) contact
• NC (Normally Closed) contact
• Output coil
• Parallel branches for contacts
• Example to create a basic latch/unlatch circuit:
• Insert an NO contact, then an NC contact in parallel with an NO contact.
• Link these to an output coil.

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Step 4: Addressing Inputs and Outputs

• Manually assign addresses:
• Double-click on contacts and write input addresses like I0.0, I0.1.
• Assign output address like Q0.0.
• Rename tags:
• Rename inputs for easy identification, e.g., START instead of I0.0 and STOP instead of I0.1.
• Rename output as LIGHT.
• Quick addressing:
• You can drag and drop addresses from the PLC device view into your ladder program.
• Typing tag names auto-fills their addresses.

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Step 5: Compiling and Downloading Logic to the PLC

• Compile your program to check for errors.
• Click the compile button.
• Confirm zero errors and warnings.
• Download your logic to the PLC:
• Click on the “Download to device” button.
• The software will search for the PLC connected to your PC.
• The PLC must be in STOP mode to download logic.
• Stop the PLC modules if necessary.
• Once downloaded, you can start the PLC again (switch from STOP to RUN mode).

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Step 6: Setting Up PLC SIM V16

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Step 7: Testing and Monitoring Your PLC Logic

• Test your ladder logic:
• Turn ON the first input, verify if the output latches ON.
• Turn ON second input to unlatch and turn output OFF.
• Monitor ladder logic:
• Use the “Monitoring” feature to view real-time bit status.
• Green means TRUE (active); Blue means FALSE (inactive).
• Understand that NC contacts indicate the inverse of the input signal.
• Use the Watch Table for monitoring:
• Create a watch table and add your PLC addresses (I0.0, I0.1, Q0.0).
• Enable monitoring to see real-time input/output states.
• Understand RUN and STOP modes:
• When in RUN mode, logic operates normally.
• In STOP mode, the PLC does not process logic—even if inputs are ON, outputs won’t change.

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Step 8: Using the Force Table for Emergency Control

• Scenario: Input is damaged but you need to control output immediately.
• Force an input by adding the address to the force table (e.g., I0.0).
• Set force to ‘1’ (ON) or ‘0’ (OFF) manually.
• Forcing bypasses actual hardware input state; software simulates the input.
• Forced inputs show an ‘F’ indicator in the software.
• Forcing causes the PLC maintenance light to turn ON, indicating active forces.
• Remove forces when done by setting forced values back to ‘0’ and stopping force.
• Maintenance light will turn OFF, indicating normal operation restored.