LMES General Process Check-out Flow - Business Interaction Specification

1. Standard Check-out Interaction Flow

2. Interaction Variables and Result Codes

Interaction Point	Direction	Data Type	Description
Completion Signal	PLC -> LMES	Bool	Completion signal. PLC sets to 1 to start the flow. PLC is responsible for resetting.
Product Code	PLC -> LMES	String	Check-out product serial number. Unique product identifier provided by PLC to LMES.
Pallet Code	PLC -> LMES	String	Check-out pallet code. Used when associating products via pallet code.
Material Code	PLC -> LMES	String	Check-out material code. Used when associating products via material code.
Equipment Processing Result	PLC -> LMES	Int	PLC judgment result. When "PLC Judgment" is enabled, PLC writes its own judgment result (1=OK, 2=NG) to this variable.
Check-out Completion Signal	LMES -> PLC	Bool	Check-out completion signal. LMES sets to 1 after processing is complete. LMES is responsible for resetting.
Check-out Result	LMES -> PLC	Int	Check-out result code. LMES informs PLC of the final status of this interaction; this is the most important result signal. PLC should execute corresponding operations based on this code: • 1: Success - Release product normally. • 6: Product Code Exception - Failed to get product code or product code is empty. Recommend alarm and pause production line, wait for manual handling. • 9: Other Exception - Unknown internal system error. Recommend alarm and pause production line, wait for manual handling. •10: Material Code Not Bound - PLC provided material code, but system cannot find corresponding product. Recommend alarm. •11: Pallet Code Not Bound - PLC provided pallet code, but system cannot find corresponding product. Recommend alarm. • 0: Reset - LMES will reset this signal to 0 after interaction is complete.
Qualified Judgment Result	LMES -> PLC	Int	Quality judgment result. LMES informs PLC of the final product quality conclusion (1=OK, 2=NG). Note: Only issued when "PLC Judgment" is not enabled.
Check-out Description	LMES -> PLC	String	Result description. When an exception occurs, LMES can write a more detailed text description.

3. Exception Troubleshooting Guide

When an exception occurs in the check-out flow (e.g., product not released, equipment alarm), please follow the steps below for troubleshooting.

Step 1: Check LMES Feedback Signals

First, check the three key result variables written by LMES to PLC:

1. Check-out Result: This is the most direct fault code.
   1. If the value is any value other than 1 (such as 6, 9, 10, 11), it means LMES encountered an error while processing business. Please refer to the description of the check-out result variable in the previous chapter to locate the cause of the problem.
2. Check-out Description: This is the most useful troubleshooting information.
   1. When an exception occurs, LMES will write detailed, readable error text to this variable. For example, "Material Code XXXXX not bound to product". Please display the content of this variable on the HMI or monitoring interface.
3. Qualified Judgment Result:
   1. Check if this value meets expectations. If the product should be NG, but this value is OK (or vice versa), you need to check the LMES judgment logic or the original data provided by PLC.

Step 2: Check Signal Handshake Flow

If the LMES feedback signal looks normal, but the flow is still stuck, please check if the standard "handshake" timing is complete. Non-standard signal states are potential sources of problems.

• Is the Completion Signal 1?
  • If the PLC does not set this signal to 1, LMES will not start the flow.
• Is the Check-out Completion Signal 1?
  • If the PLC has requested, but this signal has not been set to 1 for a long time, it means the internal logic of LMES may still be processing or a serious error has occurred. At this time, focus on viewing the content of Check-out Description.
• Has the Completion Signal been reset to 0?
  • According to the principle of "who triggers, who resets", this signal must be cleared by the PLC. If the PLC program fails to clear it, although LMES has handled this exception to ensure production line operation and can start a new flow, this non-standard state is the root cause of potential problems and must be corrected in the PLC program.
• Are the Check-out Completion Signal and other LMES signals reset?
  • At the end of the interaction, LMES should reset all signals triggered by itself. If these signals remain 1, they may interfere with the judgment of the next check-out request or generate warnings in the LMES log.

Step 3: Use LMES Station Console

If more detailed information is needed, please use the Station Console function provided by the LMES system.

• Real-time Variable Monitoring: You can see the current values of all interaction points in real time.
• Flow Log: You can see detailed business execution steps and locate specifically which step the problem occurred in.
• Warnings and Errors: All error and warning information will be highlighted.

Step 4: Special Scenario Troubleshooting

Check-in and Completion Time Consistency

• Phenomenon: When viewing processing records, it is found that the "Check-in Time" and "Completion Time" of a certain process are exactly the same.

• Cause: This is usually by design, not a system error. This happens at data collection points or passing stations. These stations physically do not perform any time-consuming processing; their only function is to record a "pass" event by scanning the product code when the product flows through. Since the product does not stay, check-in (scanning) and check-out (recording completion) occur instantaneously in logic, so the system assigns them the same timestamp.

• Troubleshooting Suggestion: Confirm whether the business type of the station is indeed data collection or passing. If so, this phenomenon is normal.