Troubleshooting Modbus Error 04 on Honeywell HC900 C50S Controller with Experion SCADA

Question:

Hello everyone, we are facing a problem with our Honeywell SCADA system. When attempting to switch the PID controller to auto mode, we encounter a Modbus error 04 - failure in the associated device. The Experion SCADA is linked to the HC 900 C50 S CONTROLLER CPU, which is displaying 4 blinking red LEDs. Can anyone assist me with this issue? Could the low voltage CPU battery be the cause of this error? Also, what type of batteries are used in the Honeywell HC900 C50S controller? The HCD software indicates that the front and rear batteries are low.

Top Replies

Are you familiar with setting the system to AUTO mode? CASC indicates involvement in a two PID Loop Cascade system.

JHarbin inquired about setting the system to AUTO in a CASC two PID Loop Cascade system. However, the current issue is that only the RSP remote set point mode is accepted due to a MOD BUS ERROR 04 Failure in the associated device. Additionally, the CPU HC900 C50S is flashing red four times and the controller's battery is low according to diagnostics.

JHarbin inquired about setting a system to AUTO mode, explaining that CASC denotes its involvement in a dual PID Loop Cascade system. The system consists of two separate PID loops within two units; one is functioning properly, while the other is displaying an error message. See the picture for a visual reference.

It appears that the PID Loop settings in the HC900 have been altered, making it inaccessible for modifications. Please compress and attach the configuration file for review. I will analyze the configuration to determine the changes made to the PID Loop settings.

I am trying to identify the root of the issue in my system. Could it be caused by the controller program or the Experian SCADA PID page? Additionally, the CPU is flashing red in four strobes. Could this be due to a low battery? According to the manual, a red flashing light indicates a low battery and that the ASYS +FSYS pins on the CPU are turned off, as shown in the picture. Both PID loops are part of the same program, so why is one working correctly while the other is malfunctioning?

Hi there! The low voltage CPU battery may indeed be a contributing factor to the Modbus error 04 that you're experiencing. When these batteries are not providing sufficient power, it could lead to the failure of the associated device. Your HC 900 C50 S CONTROLLER CPU typically utilizes lithium 3-volt batteries. Notably, per Honeywell's recommendations, you should replace both the front and rear batteries at the same time to ensure optimal performance. Be sure to follow safety precautions when replacing these batteries, given they're lithium. Updating the batteries might resolve your issue, but if not, I'd recommend contacting Honeywell's support directly for further assistance.

Hi there! Although a low voltage CPU battery could potentially lead to hardware malfunctions, I doubt it's the cause of a Modbus error. The Modbus error 04 typically indicates a failure in the associated device functioning rather than a power issue. You might want to check your device's configuration or connections. Regarding your question about the battery type, Honeywell HC 900 CPUs generally uses 3V Lithium CR2450 batteries for memory backup. Remember to handle these batteries carefully, given the chemical hazard they present. You should definitely replace them if your HCD software is indicating they are low.

Hey there, it does sound like your low voltage CPU battery could be contributing to this issue. A similar problem occurred in my system once, and after replacing the battery, the issue was resolved. Just to be precise, the Honeywell HC900 C50S Controller typically utilizes CR2477N 3V Lithium batteries. Always ensure the power is off before replacing the batteries to avoid any potential damage. If after replacing the battery, the issue persists, it could be a deeper hardware issue or something related to your Modbus configuration.

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Frequently Asked Questions (FAQ)

FAQ: 1. What does Modbus Error 04 on a Honeywell HC900 C50S Controller with Experion SCADA indicate?

Answer: - Modbus Error 04 typically signifies a failure in the associated device. In this case, it could be related to the communication between the Experion SCADA and the HC900 C50S Controller.

FAQ: 2. How can I troubleshoot the blinking red LEDs on the HC900 C50S Controller?

Answer: - Blinking red LEDs on the HC900 C50S Controller may indicate an issue. It is recommended to check the HCD software for error messages and refer to the controller's documentation for troubleshooting steps.

FAQ: 3. Could the low voltage CPU battery be causing the Modbus Error 04?

Answer: - A low voltage CPU battery in the Honeywell HC900 C50S Controller can potentially cause communication errors like Modbus Error 04. It is advisable to replace the front and rear batteries with the appropriate type specified by Honeywell.

FAQ: 4. What type of batteries are used in the Honeywell HC900 C50S controller?

Answer: - The Honeywell HC900 C50S controller uses front and rear batteries. It is important to ensure that these batteries are replaced with the correct type as indicated by Honeywell to avoid operational issues.

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