PLC Logic for Conveyor Oven Heating Control: Tailored Heating for Different Products

Introduction: Optimizing Conveyor Oven Systems with PLC Logic

Industrial automation in food processing or manufacturing often requires tailored heating solutions, especially when different products require different temperatures for optimal results. A PLC-controlled conveyor oven system can automate and optimize the heating of various products in a single process, ensuring consistent quality and efficiency. This article delves into a PLC programming solution using Omron CX-Programmer, which controls the heating process for products on a conveyor system, adjusts the oven temperature based on product type, and counts products as they undergo heating.

System Overview: How the Conveyor Oven Works

The system comprises two conveyors, Conveyor-1 and Conveyor-2, which work together to transport products into the oven. Each product—whether it’s a Red Product or a Blue Product—requires specific heating temperatures, and the oven adjusts its temperature accordingly:

• Red Products require an oven temperature of 50°C.

• Blue Products require a higher oven temperature of 75°C.

• The oven defaults to 30°C when no product is present.

In addition, the system features a counter to track how many products have successfully gone through the heating process.

PLC Logic Breakdown for Conveyor Oven Control

Rung 0: System Initialization

In the first rung, the START button (0.00) is pressed to begin the system. This sets the SYSTEM_ON memory bit (W0.00) to HIGH. By using the KEEP(011) instruction, the system remains in an active state even after the START button is released. The system will stop when the STOP button (0.01) is pressed, which sets SYSTEM_ON to LOW.

Rung 1: Conveyor and Oven Activation

Once the system is on, Conveyor-1 (100.00) and the oven (100.01) are activated. The MOV instruction moves the value 30 (default temperature) to the SV_OVEN_TEMPERATURE memory word (D100). This sets the oven temperature to 30°C when no products are detected on the conveyors.

• Conveyor-1 will run continuously, moving products onto Conveyor-2.

• When Conveyor-2 receives a product from Conveyor-1, it will move the product into the oven. The SENS_RED and SENS_BLUE sensors detect the product type and adjust the oven temperature accordingly.

Rung 2: Heating Logic for Red Products

When the SENS_RED (0.02) sensor detects a Red Product, the MOV instruction moves the value 50 to SV_OVEN_TEMPERATURE (D100), setting the oven temperature to 50°C. At the same time, the memory bit IR1_CONV2_ON (W0.01) is latched HIGH, ensuring the Conveyor-2 continues moving until the Red Product has passed through the oven. The latching mechanism ensures that the system keeps Conveyor-2 running even after the SENS_RED sensor goes LOW.

Rung 3: Heating Logic for Blue Products

Similarly, when a Blue Product is detected by the SENS_BLUE (0.03) sensor, the oven temperature is increased to 75°C by the MOV instruction, setting SV_OVEN_TEMPERATURE to 75. The memory bit IR2_CONV2_ON (W0.02) is latched HIGH, and Conveyor-2 continues to move the Blue Product into the oven. Like the Red Product sequence, this latching ensures Conveyor-2 runs without interruption, even when the SENS_BLUE sensor goes LOW.

Rung 4: Conveyor-2 Movement

In this rung, Conveyor-2 is activated to transport products into the oven. Conveyor-2 (100.02) will run when either IR1_CONV2_ON (W0.01) or IR2_CONV2_ON (W0.02) memory bits are in the HIGH state. This ensures that Conveyor-2 only operates when a product is present on Conveyor-1 and has been detected by the appropriate sensor (Red or Blue).

Rung 5: Product Count

A critical feature of this system is its ability to track the number of products processed. When the SENS_OUT (0.04) sensor detects that a product has exited the oven, the MOV instruction increases the COUNT_PRODUCT memory word (D0) by 1. This function counts how many products have successfully passed through the oven heating process.

Rung 6: Counter Reset

To reset the product count, the RESET_COUNTER button (0.05) can be pressed. This sets the COUNT_PRODUCT memory word (D0) back to 0, preparing the system for a new counting cycle. The reset action is useful for tracking batches or specific time intervals in a production run.

System Benefits and Operational Efficiency

Tailored Heating for Different Products

One of the most significant advantages of this system is its ability to automatically adjust oven temperatures based on the product type. By using sensors to detect whether a Red Product or a Blue Product is on the conveyor, the oven temperature is adjusted accordingly. This ensures that each product receives the precise temperature required for optimal results, improving product quality and reducing energy wastage.

Continuous Operation and Monitoring

The use of latching memory bits ensures continuous operation of Conveyor-2, even if the sensors stop detecting the product. This uninterrupted operation allows the system to maintain a steady flow of products through the oven, improving throughput and reducing downtime.

Product Tracking and Count

The product count feature provides valuable data for production monitoring. This functionality is essential for reporting, inventory control, and quality assurance, as it ensures that each product that goes through the oven heating process is tracked.

Flexibility and Control

The system's ability to reset the product counter allows operators to track production in different batch sizes. The RESET_COUNTER button ensures that the system remains flexible, allowing for easy recalibration between production cycles.

Conclusion: Enhancing Production Efficiency with PLC Control

The integration of PLC logic into a conveyor oven system offers numerous benefits, including tailored heating for various products, continuous monitoring, and automatic adjustments. By using Omron CX-Programmer, this system not only controls the heating process but also counts products and ensures efficient operation. With its robust control over conveyor systems, oven temperatures, and product tracking, the PLC-driven conveyor oven is a vital tool for optimizing manufacturing processes.