LMES General Process Check-in Flow - Business Interaction Specification

1. Standard Check-in Interaction Flow

2. Interaction Variables and Result Codes

Interaction Point	Direction	Data Type	Description
Check-in Signal	PLC -> LMES	Bool	Check-in signal. PLC sets to 1 to start the flow. PLC is responsible for resetting.
Product Code	PLC -> LMES	String	Check-in product serial number. Unique product identifier provided by PLC to LMES.
Material Code	PLC -> LMES	String	Check-in material code. Used when associating products via material code.
Pallet Code	PLC -> LMES	String	Check-in pallet code. Used when associating products via pallet code.
Check-in Completion Signal	LMES -> PLC	Bool	Check-in completion signal. LMES sets to 1 after processing is complete. LMES is responsible for resetting.
Processing Type	LMES -> PLC	Int	LMES issues product processing type, indicating product processing type (Normal/Spot Check/Rework)
Check-in Result	LMES -> PLC	Int	Check-in 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. • 2: Product Status Exception - Intercept product, trigger alarm, remove product from production line. • 3: Product Duplicate Code Exception - Intercept product, prevent repeated processing. • 4: Product Missed Process Exception - Intercept product, prevent missed process product inflow. • 5: MES System Exception - Pause production line, wait for recovery, MES system fault handling • 6: Product Code Exception - Failed to get product code or product code is empty. Recommend alarm and pause production line, wait for manual handling. • 7: Check-out Without Processing - Product checks out but is not processed, released to buffer area, special handling process. • 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.
Check-in 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-in flow (e.g., product not released, equipment alarm), please follow the steps below for troubleshooting.

Step 1: Check LMES Feedback Signals

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

1. Check-in Result: This is the most direct fault code.
   1. If the value is any value other than 1 (such as 2, 3, 4, 5, 6, 7, 9, 10, 11), it means LMES encountered an error while processing business. Please refer to the description of the check-in result variable in the previous chapter to locate the cause of the problem.
2. Check-in 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.

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-in 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-in 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-in 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-in 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

Product Model Mismatch

• Error Type
  • Recipe Product Model Mismatch: Product historical model ≠ Process application recipe product model
  • Work Order Product Model Mismatch: Product historical model ≠ Process segment work order required product model
• Troubleshooting Steps
  • Confirm Type: Check Recipe Issuance Method
  • Method 0 (Only Work Order can operate issuance): The system must be able to obtain the work order issued by the current segment and determine the product model based on it. If there is no work order, check-in is prohibited.
  • Method 1 (Only Process Recipe can operate issuance): The system relies on the recipe applied by the current process to determine the product model.
  • Method 2 (Issue recipe when process identifies product): The system relies on the recipe applied by the current process to determine the product model, ensuring that the recipe has been correctly switched before check-in.