eDNC Special Character Fix

Real-time file watcher that automatically removes invalid special characters from DNC (Direct Numerical Control) program files.

Problem

Some legacy DNC systems and communication protocols add padding or termination bytes that modern CNC controllers cannot process correctly. Common problematic characters include:

Byte	Hex	Name	Description
255	0xFF	Fill	Padding/fill character
0	0x00	NULL	Null character
26	0x1A	SUB	Ctrl+Z / EOF marker
127	0x7F	DEL	Delete character

Solution

This utility monitors a folder for DNC files and automatically strips specified characters as soon as files are created or modified.

Installation

1. Copy the project folder to C:\eDNC-Fix\ on the DNC workstation
2. Run Install-ScheduledTask.ps1 as Administrator

C:\eDNC-Fix\
├── eDNC-SpecialCharFix.ps1
├── Run-eDNCFix.bat
├── Install-ScheduledTask.ps1
└── README.md

Install as Scheduled Task (Recommended)

# Run as Administrator
C:\eDNC-Fix\Install-ScheduledTask.ps1

# To remove
C:\eDNC-Fix\Install-ScheduledTask.ps1 -Uninstall

The scheduled task:

• Starts at system boot (before any user logs in)
• Runs as SYSTEM with highest privileges
• Auto-restarts if it crashes
• Watches C:\Dnc_Files\Q for *.pun files

Run Manually (Alternative)

Double-click Run-eDNCFix.bat - it will auto-elevate to Administrator via UAC.

Configuration

Default settings (edit eDNC-SpecialCharFix.ps1 to change):

Setting	Default	Description
WatchFolder	C:\Dnc_Files\Q	Folder to monitor
FileFilter	*.pun	File pattern to watch
IncludeSubfolders	$true	Watch subdirectories
CharactersToRemove	@(255)	Byte values to strip (0xFF)

Auto-Update

The script automatically checks for updates every 5 minutes by reading:

S:\DT\cameron\eDNC-Fix\version.ini

To deploy an update:

1. Update version.ini with the new version number
2. Copy new files to S:\DT\cameron\eDNC-Fix\
3. Running instances will auto-update within 5 minutes

version.ini format:

[eDNC-Fix]
Version=1.4.0

Output

The script displays real-time activity:

========================================
 eDNC Special Character Fix v1.0.0
========================================

Configuration:
  Watch Folder:    C:\Dnc_Files\Q
  File Filter:     *.pun
  Subfolders:      True
  Removing bytes:  255 (0xFF)

Watching for files... Press Ctrl+C to stop

2025-12-12 08:30:15 | Created | PART001.pun
  [CLEANED] Removed 3 byte(s)
2025-12-12 08:30:22 | Changed | PART002.pun
  [OK] No special characters found

Requirements

• Windows PowerShell 5.1 or later
• Read/Write access to the watch folder

Troubleshooting

"Watch folder does not exist"

Create the folder or specify a different path with -WatchFolder.

"File locked" errors (v1.0.0)

If using v1.0.0, update to v1.1.0 for improved file locking handling with exponential backoff and stability checks.

Script doesn't detect files

• Verify the file extension matches -FileFilter
• Check that -IncludeSubfolders is set correctly
• Ensure the script has permissions to the folder

"[WAIT] File still being written..."

This is normal behavior. The script waits for the file size to stabilize before processing, which means eDNC is still transferring the file. The script will automatically process it once the transfer completes.

"[RETRY] File locked..."

The script uses exponential backoff (500ms → 1s → 2s → 4s → up to 16s) for up to 10 attempts. If you see [FAILED] messages, eDNC may be holding the file longer than expected.

Version History

Version	Date	Changes
1.5.0	2025-12-12	API logging to ShopDB (started, cleaned, failed, stopped events)
1.4.0	2025-12-12	Auto-update from S:\DT\cameron\eDNC-Fix\version.ini every 5 min
1.3.1	2025-12-12	Added Install-ScheduledTask.ps1 for running as SYSTEM service
1.3.0	2025-12-12	Fixed header UI, live status/stats, auto-elevate to Administrator
1.2.1	2025-12-12	Added GE Aerospace ASCII banner
1.2.0	2025-12-12	Immediate processing: 50ms delay, aggressive retry (100ms+), 15 attempts
1.1.0	2025-12-12	Improved file locking: stability check, exponential backoff, debouncing
1.0.0	2025-12-12	Initial release

Author

GE Aerospace - Rutland