Honeywell ControlEdge HC900 Controller Troubleshooting Manual

Verify version consistency: Use Designer software to connect the main control and backup control separately, click "Controller" ->"Properties" to view the firmware version and project configuration version number (checked through File Properties). If there is inconsistency, upgrade the backup control to be exactly the same as the main control. Note: Redundant systems require that the hardware model, firmware, and configuration file hash values of two CPUs are completely identical.

Test battery status: Open the front cover of the C75 module and measure the battery voltage. The TL5903 lithium battery has a nominal voltage of 3.6V and must be replaced when it is below 2.5V. Place the controller in Program mode and disconnect the power before replacement, and record all configurations (backed up to SD or PC). After replacement, download the configuration again and resume operation.

RSM switch check: Rotate the key switch on the RSM to the "Auto" position (not "Force"). Refer to the output parameters of the "Redundancy Status" function block in Designer and confirm that "Switch_Snable" is set to TRUE.

Force switch test: Manually trigger the switch using the "Redundancy Control" function block in Designer (or through the buttons on RSM). Observing LED changes: The "Lead" LED of the main control goes off, and the "Lead" LED of the backup control lights up. If the I/O communication is still abnormal after switching, use the diagnostic function block "System Monitor" to read the heartbeat status of each remote rack (see the remote I/O fault section below).

Restore synchronization: If the backup controller is offline for a long time, full synchronization needs to be performed again. Firstly, ensure that the backup control is in "Program" mode, and then select "Redundancy" ->"Synchronize now" in Designer. The system will copy all the configuration and operating parameters of the main control to the backup control, which may take several minutes, during which the control will not be affected.

Preventive measures: Conduct a manual redundancy switch test once every quarter and check the battery voltage records of both CPUs. Regularly backup configuration files to the project server.

3.2 Unable to recognize or maintain bad channel data values after hot plugging of I/O modules

phenomenon

After replacing the faulty analog input module (such as 8-channel UIO), the corresponding channel in the Designer software displays "????" or "Bad", and the actual on-site signal (such as 4-20 mA) cannot be read.

After replacing the digital output module, the corresponding DO point cannot control the on-site equipment, and the module status LED displays red.

An entry for 'I/O module mismatch' or 'Configuration error' appears in the controller log (Event Log).

Possible reasons:

The newly inserted module model does not match the model specified in the configuration (for example, the original module was a 16 channel high-level AI, mistakenly inserted as an 8-channel universal AI).

The module was not fully secured during insertion, resulting in poor contact of the backplane connector.

The controller scanning program failed to automatically trigger module enumeration (commonly seen in some early firmware versions or redundant systems).

The channel configuration of the module (such as input type, range, filtering) is lost due to EEPROM damage.

Exclusion steps:

Confirm model consistency: Check the product code on the side of the module (e.g. 900AI8-0100 is an 8-channel universal AI, 900AI16-0100 is a 16 channel high-level AI). Compare the "Module Type" setting of the slot in Designer. If there is inconsistency, it is necessary to replace the correct model or modify the configuration (modifying the configuration requires online download, which may cause temporary disturbance).

Re plug and observe self-test: While the system is running, completely unplug the module, wait for 5 seconds, and then forcefully push it in until the upper and lower buckles "click" to lock. Observe the "OK" or "PWR" LED on the module: normally it should be green and constantly on. If the LED flashes red, it indicates a module self-test failure or backplane communication error.

Force reinitialization: In Designer, enter the "I/O Configuration" view, right-click on the corresponding I/O rack, and select "Re initialize I/O. This operation will force the controller to re enumerate all modules on this rack, without affecting other racks. Note: For redundant CPU systems, this operation must be performed on both CPUs (or wait for automatic repair of redundant synchronization).

Check channel diagnostic information: Double click the I/O module to open the module details window. HC900 provides diagnostic status for each channel (such as "Open Wire", "Overlange", "Underrange", "Input Error"). For analog inputs, the most common is "Open Wire" - check if the sensor wiring on site is disconnected. When configuring the UIO module as a digital output, a "Short Circuit" appears - check if the load impedance is too low.