fanuc-program-inspection-methodology.md

title	FANUC Robot Program Inspection Methodology — Systematic Check Guide
domain	fanuc
subdomain	quality
tags	inspection checklist program-review signal-check collision-zone fine-point quality
status	published
source	internal-training
confidence	0.9
created	2026-07-14

Problem

Robot programs need systematic inspection before production to catch signal mapping errors, safety violations, and logic bugs. Without a structured methodology, inspectors miss critical issues or check inconsistently across different robots.

Solution

Inspection Categories

1. Signal Check (All Robots)

Verify all DI/DO/GI/GO signals against the configuration standard:

Signal ranges:
  DIDO-PLC:        1-512        (PLC communication)
  DIDO-Connection:  513-2648     (ISV vision, etc.)
  DIDO-Tool:        2649-4096    (end effector tools)

For each signal:

• Verify signal number matches configuration standard
• Verify signal name matches function
• Flag undefined signals with suggested purpose

2. Collision Zone FINE Point Check

Critical safety check: The motion command BEFORE releasing a collision zone must use FINE positioning (not CNT).

Search pattern:

Search: "CollZone Release" or "CollZone, Release"
For each match:
  → Find the last motion command BEFORE the release
  → Verify it uses FINE (not CNT50, CNT100, etc.)

Entering a collision zone (Request) does NOT require FINE — only exiting (Release) does.

3. Program Logic Check

Initialization sequence:

• TIMER_START present at program start
• MI01_CMN Init call present
• Proper HOME position setup

Decision Code handling:

• WAIT GI[5] present for decision code
• SELECT logic for multi-path branching
• All branches lead to valid programs

Tool change check:

• TIP_CHECK call present where needed
• Tool change sequence correct (dock/undock pairs)

End sequence:

• MOVE_HOME at program end
• TIMER_STOP at program end
• Proper signal cleanup

4. Fixture Check

Search: "Fixture IN" → verify corresponding "Fixture OUT"
For each fixture:
  → IN/OUT must be paired
  → IN before entering work area
  → OUT after leaving work area

5. Application-Specific Check

Spot welding:

• SPOT instruction parameters (SD/P/t/S/ED)
• SPOT instruction must be at FINE point
• Non-weld motions can use CNT

Gluing:

• Speed between SS[1] and SE ≤ 500mm/sec
• SS[1] marker present at glue start
• SE marker present at glue end
• GO[22] parameter for glue switching

SPR (Self-Piercing Rivet):

• RivetNo./NextRivetNo./GunOpen parameters correct
• MI14_SPR instruction at FINE point
• Magazine refill signal DI[1180] checked

Inspection Report Template

## Inspection Summary
| Category | Items | Passed | Rate |
|----------|-------|--------|------|
| Signal Check | X | X | X% |
| Collision Zone FINE | X | X | X% |
| Application Check | X | X | X% |
| Program Logic | X | X | X% |
| **Total** | **X** | **X** | **X%** |

## Issues Found
| # | Issue | Location | Severity |
|---|-------|----------|----------|
| 1 | ... | Line XX | Low/Med/High |

Program Naming Convention

Connection: RobotID_CarModel_ProcessOrder_Process_WorkStation
Example: UB030R01_MS11_01_PICK_JR1

Action: RobotID_ToolID_Process_ToolID
Example: UB030R01_MS11_01_WELD_JR1

Verification

1. Run signal check on a known-good program — should pass 100%
2. Intentionally change a FINE to CNT before CollZone Release — should be caught
3. Remove a Fixture OUT call — should be flagged as missing pair
4. Run full inspection on a new program — verify all categories checked

Notes

• Always check collision zone FINE points first — this is the most common safety issue
• Signal definitions change between projects — always use the current configuration standard
• Program logic checks should be automated where possible (HTML checker tool)
• Inspection results should be documented for traceability