How to Remove a Mercury SIO Device in QxControl

Learn how to safely remove a Mercury SIO daughter board, like an MR50, from a controller in QxControl and update your device configurations.

August 3, 2026 By Tanner Nack

This guide explains how to remove a Mercury SIO daughter board (such as an MR50) from a controller in QxControl. Removing obsolete or disconnected hardware ensures your security device configurations remain accurate and up-to-date.

This workflow applies to security administrators and system technicians. Use this process when decommissioning hardware, replacing a faulty board, or restructuring your Mercury security inventory.

To manage your device inventory in QxControl, follow these steps to remove an SIO daughter board.

Navigate to your device dashboard in QxControl.

Step #2: Click Edit Device on the controller you want to modify. — Click **Edit Device** on the controller you want to modify.

Ensure you have selected the correct device. Removing an active SIO module will sever connections to associated doors and lead to a loss of historical hardware data.

Step #3: Scroll down to your connected hardware modules. Locate the MR50 SIO daughter board you wish to remove, and click the Delete (trash can) icon in the top-right corner of its card. — Scroll down to your connected hardware modules. Locate the MR50 SIO daughter board you wish to remove, and click the **Delete** (trash can) icon in the top-right corner of its card.

Step #4: In the warning dialog that appears, click the red I understand, Remove button to confirm. — In the warning dialog that appears, click the red **I understand, Remove** button to confirm.

Step #5: Click ✓ Save Device in the bottom-right corner to apply the new configuration to your controller. — Click **✓ Save Device** in the bottom-right corner to apply the new configuration to your controller.

If you encounter an "unknown error" during save, verify that your Gateway dropdown selection is configured correctly and that the controller is online.

Q: Why am I getting an "unknown error" when trying to save after removing a device?

A: This can happen if the device's Gateway configuration is incomplete or if the controller has temporarily lost connection. Ensure the Gateway field is correctly populated before saving.

Q: What happens to the doors connected to the MR50 when I remove it?

A: All associated door configurations and historical access data tied specifically to that hardware module will be lost permanently once removed.

Term	Definition
QxControl	The physical security and access control management software platform by Qumulex.
Mercury SIO	Serial Input/Output daughter boards (like the MR50) used to interface with readers, doors, and alarms.
MR50	A specific model of single-reader Mercury access control board used to manage a single door.
Gateway	The networking component or service that bridges communication between the cloud software and local physical security panels.