How to check PLC program status using memory address or programmable bit

Question:

I'm curious to know which memory address bit or programmable bit indicates the current status of the program: running, stopped, etc. Thank you for your help.

Top Replies

I am currently utilizing the Omron CJ2H CPU66-EIP programmable logic controller (PLC) system.

PLCs typically do not have running/stopped bits because the PLC program cannot change a bit when stopped. However, there are instances where a running/stopped system bit can be accessed via Modbus directly from the processor. If you require a heartbeat signal or similar functionality, you will need to code it into the PLC and monitor the bit changes on the HMI.

The error diagnosis feature in Mitsubishi PLCs includes specialized bits and registers that are accessible when the PLC is powered up. This information can be displayed on HMIs for monitoring. While other PLCs may have similar diagnostic capabilities, it is recommended to consult the PLC's manual or contact the manufacturer for more information on how to read these diagnostics using an HMI.

Typically, the status of a program (running, stopped, etc.) isn't determined by a single memory address bit or programmable bit. It's the operating system that monitors and manages the status of all processes. However, you could investigate concepts such as program counters or the use of flags within a program. These might not give you the exact running or stopped status, but they can provide insight into the flow and state of a program.

More Replies →

Streamline Your Asset Management
See How Oxmaint Works!!

✅   Work Order Management

✅   Asset Tracking

✅   Preventive Maintenance

✅   Inspection Report

We have received your information. We will share Schedule Demo details on your Mail Id.

To add a comment, please sign in or register if you haven't already..   

Frequently Asked Questions (FAQ)

FAQ: FAQs:

Answer: 1. How can I check the PLC program status using memory address or programmable bit? - To check the program status, you can monitor specific memory addresses or programmable bits that indicate whether the program is running, stopped, or in a certain state.

FAQ: 2. Which memory addresses or bits in a PLC typically indicate the program status?

Answer: - The memory addresses or bits that indicate the program status can vary depending on the specific PLC model and programming method. It is recommended to refer to the PLC's documentation or consult with the manufacturer for the exact addresses or bits to monitor.

FAQ: 3. How can I identify the memory address or bit that indicates the program status in my PLC?

Answer: - You can refer to the PLC's programming software, user manual, or online resources provided by the manufacturer to identify the specific memory address or bit that indicates the program status. Additionally, reaching out to the manufacturer's technical support team can also help clarify this information.

Ready to Simplify Maintenance?

Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.

Request Demo  â†’