IC693CPU363 Firmware Upgrade Interruption: Causes, Bootrom Recovery, and Practical Solutions for Industrial Automation
Firmware interruptions during PLC updates can halt factory automation lines. The IC693CPU363 module from GE Fanuc Series 90-30 often suffers a specific failure. A WinLoader session may stop mid-transfer. Consequently, the serial port becomes unresponsive. This article explains the mechanism and provides a field-proven recovery path.
Why Interrupted Upgrades Corrupt Serial Communication
The Bootloader Handshake Cannot Complete
The IC693CPU363 runs on a 25 MHz 80386EX processor. It offers 240K bytes of user memory. Flash memory holds both firmware and user data. When a WinLoader update aborts, the firmware region may contain partial data. As a result, the CPU cannot initialize its communication drivers. The SNP protocol stays inactive until valid firmware loads.
The Circular Dependency That Blocks Standard Recovery
Standard recovery through Proficy or Logicmaster requires a working communication driver. However, that driver lives inside the corrupted firmware. Therefore, a circular dependency occurs. In addition, the watchdog timer may trigger when reading corrupted flash. This protective mechanism further prevents normal operation. Users must bypass the standard software path entirely.
The Hardware Shorting Pads on the CPU363 Board
How CLR MEM Pads Enable Bootrom Entry
The IC693CPU363 circuit board contains specific shorting pads. These pads are marked CLR MEM or similar designations near the board edge. When shorted during power-up, they force the CPU into bootrom recovery mode. This mode operates independently of the main firmware image. Therefore, it can accept a fresh firmware download even when flash is corrupted.
Why the Bootrom Code Remains Reliable
The bootrom code resides in protected memory. It initializes a minimal communication interface for recovery operations. This hardware-level access provides the only reliable path after a failed upgrade. In industrial automation, such low-level recovery features are critical for minimizing downtime in factory automation systems.
Identifying the Correct Shorting Pads and Safety Precautions
Locating the Pads on the CPU363
Before attempting the shorting procedure, users must identify the correct pad locations. The CPU363 circuit board requires partial disassembly for access. The front cover slides off after releasing two retaining tabs. The shorting pads are typically located near the board edge. They appear as two exposed solder points or a jumper header.
Electrostatic Discharge and Power Safety
Electrostatic discharge protection is mandatory during this process. The CPU module contains sensitive CMOS components. Always power down the rack completely before removing the CPU. Verify that the power supply provides 890 milliamps at +5 VDC before reinstallation. These precautions protect both personnel and expensive control systems hardware.
Step-by-Step Bootrom Recovery Procedure
Preparing the Hardware and Serial Connection
Perform the following sequence precisely to force bootrom entry. First, power down the entire Series 90-30 rack and remove the CPU module. Second, locate the CLR MEM shorting pads on the circuit board. Third, identify a suitable conductive tool with insulated handles. Fourth, connect a serial cable between the PC and the power supply port before power-up.
Forcing Bootrom Mode During Power-Up
The power supply port provides the primary SNP connection. Fifth, short the pads together and hold them in contact. Sixth, apply power to the rack while maintaining the short. Seventh, continue holding the short for approximately 5 to 10 seconds after power stabilizes. Eighth, release the short and observe the CPU LEDs.
Confirming Bootrom Mode and Starting WinLoader
The OK LED should indicate bootrom mode with a distinctive pattern. Finally, launch the WinLoader utility and initiate the firmware transfer. This method works even when standard serial recovery fails. Consequently, it remains the preferred field solution for corrupted IC693CPU363 modules.
Serial Cable and Port Configuration for Recovery
Required Hardware for RS-232 to RS-485 Conversion
The recovery communication path requires specific hardware. An IC690ACC901 Mini Converter Kit provides the necessary RS-232 to RS-485 conversion. The cable connects to the 15-pin D-shell connector on the power supply module. This port serves as the built-in SNP access point.
Which Ports to Use and Which to Avoid
Do not attempt recovery through the front-panel RJ-45 ports. Those ports depend on the corrupted firmware drivers. The power supply port maintains bootrom-level access. Configure the PC serial connection for 19200 baud, 8 data bits, 1 stop bit, and no parity as the baseline parameters. Verify that the serial port assignment in Windows matches the physical connection.
WinLoader Configuration After Bootrom Entry
Matching Software Version to Hardware Revision
Once the CPU enters bootrom mode, WinLoader can establish communication. The software version must support the IC693CPU363 hardware revision. Select the correct COM port and configure the timeout value appropriately. Increase the request timeout to 25 seconds for large firmware transfers.
Transferring the v10.60 Firmware Image
The v10.60 firmware image file must be intact and verified before transfer. Begin the download process and monitor progress indicators carefully. Do not interrupt the transfer for any reason. A complete v10.60 image requires approximately 2 to 4 minutes depending on serial speed. After completion, cycle power to the rack normally.
Post-Recovery Verification and User Data Restoration
What Gets Cleared During Recovery
The firmware upgrade process clears all user information from RAM. This includes the program, configuration, CPU ID, and status tables. After successful recovery, restore the application from a backup folder. The SNP ID must be set separately using programming software.
Verifying Firmware Revision and Fault Tables
Verify the firmware revision through the PLC Status screen. The displayed software revision should read 10.60 or the appropriate version string. Check the fault tables for any remaining errors. Perform a full store-to-flash operation to commit all configuration data. Test serial communication on all three ports to confirm full functionality.
Preventing Future Upgrade Interruptions
Best Practices for Stable Firmware Updates
Several measures reduce the risk of interrupted firmware upgrades. Always use a quality serial cable with proper shielding. Verify stable power supply voltage before beginning any flash operation. Close all unnecessary applications on the programming PC. Disable Windows power management features that might interrupt serial communication.
Using a UPS and EEPROM for Extra Protection
Consider using a UPS for both the PC and PLC rack during critical updates. The IC693ACC305 EEPROM option provides program retention independent of battery state. This module stores the application in non-volatile memory. After a successful firmware upgrade, store the program to EEPROM as a recovery baseline. Document the firmware version and configuration settings for future reference.
Application Case: Recovering a Corrupted IC693CPU363 on a Packaging Line
Scenario and Solution
A food packaging plant experienced a power failure during a firmware update. The IC693CPU363 module became unresponsive on all front-panel ports. The maintenance team followed the bootrom recovery procedure. They shorted the CLR MEM pads during power-up. WinLoader then accepted a fresh v10.60 image. The line returned to service within 45 minutes.
Key Lesson for Industrial Automation Teams
This case highlights the value of hardware-level recovery in PLC and DCS environments. Moreover, it shows why factory automation teams should document bootrom procedures. A small conductive tool and a serial converter can save hours of downtime.
Frequently Asked Questions
Can I recover an IC693CPU363 without opening the module?
No. The bootrom recovery mode requires shorting the CLR MEM pads. These pads sit on the circuit board inside the module. You must remove the front cover and access the board directly. Standard serial recovery through front-panel ports will not work after a corrupted firmware update.
Why does the SNP protocol remain inactive after an interrupted upgrade?
The SNP protocol depends on firmware stored in flash memory. When the upgrade aborts, the firmware region may contain partial data. Consequently, the CPU cannot initialize its communication drivers. The SNP slave protocol cannot establish itself on any port until valid firmware loads.
What serial parameters should I use for WinLoader recovery?
Configure the PC serial connection for 19200 baud, 8 data bits, 1 stop bit, and no parity. These parameters serve as the baseline for bootrom communication. Also, increase the request timeout to 25 seconds for large firmware transfers. Verify the COM port assignment in Windows matches the physical connection.
Will I lose my PLC program after a bootrom recovery?
Yes. The firmware upgrade process clears all user information from RAM. This includes the program, configuration, CPU ID, and status tables. Therefore, you must restore the application from a backup folder. After restoration, set the SNP ID separately and perform a full store-to-flash operation.
How can I prevent future firmware upgrade interruptions?
Use a quality shielded serial cable and verify stable power supply voltage. Close unnecessary applications on the programming PC. Disable Windows power management features. Consider a UPS for both the PC and PLC rack. Store the final program to an IC693ACC305 EEPROM as a recovery baseline.
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