Troubleshooting a Fault Light Issue Linked to GSV Instruction - ControllerDevice 12640 Error

Question:

I am investigating a small "recoverable" system error that is causing a fault light to appear on a machine, despite no obvious issues affecting operations. Upon further investigation, I have identified that the error is linked to a specific bit in a GSV (Get System Value) instruction, which is sourcing its data from "ControllerDevice" as the Class Name. The current number associated with this is 12640, and the fault is specifically related to the 9th bit in this number. I have conducted extensive research online to understand the significance of the "ControllerDevice" number and its origin within the PLC. Could this be hardware-related? Where is the 12640 number originating from? Any insights on the location of the triggering bit, excluding the "DS_TOGGLE_BIT," would be appreciated as I am using it for troubleshooting purposes to isolate the fault causing the cabinet light to illuminate.

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The ControllerDevice signifies that the device receiving values is the controller. By editing the rung or creating a new GSV, you can access a dropdown menu with various selections available. Additionally, by right-clicking and selecting "instruction help," you can find more information under 'GSV/SSV Object.' Within this section, you will find ControllerDevice, which provides a list of data that can be obtained from the controller using the GSV instruction. This includes status bits such as Flash Update, Faulted Modes, Run, and Program. By examining your screenshot, you can determine if the device is in RUN mode, has a recoverable minor fault, or if the key is in a remote position. Explore the controller properties to view the current error code and error associated with the minor fault.

By pressing "F1" while selecting the GSV instruction, you can access online help. Navigate to "GSV/SSV Objects" and select "ControllerDevice". Here, you will find a table displaying the Status as an INT tag with various status bits indicating different meanings. These include reserved statuses, flash update status, faulted modes, and controller status bits indicating keyswitch position and controller mode. Bit 8 specifically represents a "Recoverable minor fault". To access the minor fault codes, refer to manual 1756-PM014 which recommends using a GSV to retrieve the FaultLog object's MinorFaultBits attribute. This manual also provides a link to a spreadsheet containing minor and major fault codes for reference.

For an @OkiePC-friendly link, visit the document at https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-rm003_-en-p.pdf#page=162.

From a PLC standpoint, the number 12640 you're seeing might be a status code that's specifically tied to the GSV instruction. As you might be aware, these status codes are in binary and any particular bit could trigger the fault light if its value changes. As for bit 9, it might represent a certain event or status in the system, though I can't pinpoint which without more information. As for the "ControllerDevice" class, it generally refers to properties and status of the controller itself. However, you should consult your PLC's documentation for specific meaning of the classes, bits, etc. If it's not a programming error, it could be a hardware fault.

It sounds like you’re digging deep into a complex issue! The "ControllerDevice" number 12640 could be related to a specific configuration or status within your PLC, so it might be worth checking the associated I/O modules or any connected devices that could be linked to that class name. The 9th bit sounds like a possible status indicator or fault flag, so if it correlates to something specific like overcurrent or temperature, it could be reflecting a transient state from hardware. Have you reviewed any recent changes made to the system or checked the wiring for intermittent connections? Sometimes physical connections can introduce ghost faults that don't impact performance but trigger these kinds of errors.

It sounds like you're on the right track by examining the GSV instruction and the specific bit within "ControllerDevice." The number 12640 could be a predefined value or configuration parameter specific to your PLC model, which may relate to a specific hardware function or status. Regarding the 9th bit, if it’s not the "DS_TOGGLE_BIT," you might want to check if it corresponds to any hardware diagnostics or communication errors. Also, investigating the PLC’s documentation could reveal more about the definitions of these bits and help trace the source of the issue—sometimes these faults can stem from wiring, sensors, or even firmware-related anomalies. Keep an eye out for any recent changes in the system that could have triggered this too!

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Frequently Asked Questions (FAQ)

FAQ: 1. What could be causing a fault light to appear on the machine despite no operational issues?

Answer: - The fault light issue could be linked to a specific bit in a GSV instruction, potentially sourced from the "ControllerDevice" Class Name with the number 12640 associated with it.

FAQ: 2. Is the fault related to a hardware issue?

Answer: - It is possible that the fault related to the specific bit in the GSV instruction sourced from the "ControllerDevice" Class Name may be hardware-related, which is causing the fault light to illuminate.

FAQ: 3. Where is the number 12640 originating from in the context of the error?

Answer: - The number 12640 associated with the GSV instruction error could be originating from the PLC system, potentially indicating a specific parameter or value within the system that is triggering the fault.

FAQ: 4. How can I locate the triggering bit within the GSV instruction for troubleshooting purposes?

Answer: - To locate the triggering bit within the GSV instruction, excluding the "DS_TOGGLE_BIT," you may need to analyze the specific bits within the number 12640 to isolate the fault causing the fault light to illuminate on the machine's cabinet.

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