Procon MelCOMMS MINI - User Manual

Questions and Answers

J
Jennifer MorganAug 15, 2025
How to troubleshoot a Procon MelCOMMS MINI Media Converter that does not power up?
- P
  Patricia HillAug 15, 2025
  If the Procon Media Converter unit does not power up and the power LED is off, here are a few things to check: 1. **Fused Spur:** Ensure that there is power coming from the fused spur. 2. **Power Supply:** Check the 230V mains voltage input to the power supply and the 24VDC output. 3. **Power Supply Fuse:** Inspect the fuse and replace it if necessary.
B
Benjamin CookAug 26, 2025
What to do if Fault LED is ON and buzzer is OFF on Procon MelCOMMS MINI?
- M
  Mitchell PachecoAug 26, 2025
  If the fault LED is ON but the buzzer is OFF on your Procon Media Converter, it means a fault exists and the mute button has been pressed. To identify the cause of the fault, refer to the troubleshooting steps for when the ‘Fault LED and buzzer are ON’.
R
ramirezjudyNov 5, 2025
What to do if the Fault LED and buzzer are ON on Procon Media Converter?
- R
  richard01Nov 5, 2025
  If the Procon Media Converter's fault LED and buzzer are activated, it could be due to several reasons: * The fault code read from the indoor unit is not 8000 (which indicates 'OK'). In this case, check the indoor units for any issues. * The high temperature alarm has been triggered. Inspect for indoor unit faults or other potential causes of high inlet temperature. * The number of configured indoor units might be incorrect. Verify that the unit configuration is accurate. * The MelcoBEMS MINI (A1M) units might have invalid addressing. Ensure each unit has a unique Modbus address (Slave ID), starting from address 1. * The MelcoBEMS MINI (A1M) units might not be powered on. Check that the two LEDs on all connected units are either ON or flashing. * There might be an RS-485 wirin...

Summary

Preface

Safety warnings

Crucial safety advisories for product operation and handling.

Disclaimer

Legal disclaimers regarding product use and warranty.

4. Getting Started

4.1. Unpacking

Instructions for safely unpacking the MeICOMMS MINI and its components.

4.2. Before switching ON

Essential checks and preparations before powering the unit on.

5. Installation

5.1. Physical connection

Steps for physically mounting and securing the unit.

5.2. Power supply

Details on connecting the unit to the mains power supply safely and correctly.

5.3. Modbus RS-485 connection

Instructions for establishing Modbus RTU communication via RS-485.

5.4. Configuration

Procedures for configuring the unit's settings using DIP switches and inputs.

5.5. Initial Power ON

Steps for the first power-up of the unit after installation and configuration.

5.6. Status Indicators

Explanation of the unit's status LEDs and indicators for monitoring operation.

6. Control Functionality

6.1. Automatic Mode

Details on the automatic operation, including Backup & Rotate functionality.

6.2. Manual Mode

Explanation of how to operate the unit in manual control mode.

6.3. Rotation Test Mode

Procedure for testing the unit's rotation functionality.

6.4. Modbus Slave Test Mode

Instructions for operating the unit in Modbus slave test mode.

Appendix A - Compatible Air-To-Air units

The Procon MelCOMMS MINI is a standalone controller designed to provide run/standby (backup and rotate) functionality for between 2 and 8 indoor air-to-air units. It interfaces with these units via MelcoBEMS MINI (A1M) adapters. The device is intended for use in non-residential/non-domestic environments, though it can be used in residential settings with potential radio frequency interference requiring corrective measures.

Function Description:

The primary function of the MelCOMMS MINI is to manage the operation of multiple split air conditioning systems in a cyclical manner, ensuring that units share the cooling load and providing backup in case of failure. This is achieved through its "Backup & Rotate" functionality, which is active when the front panel switch is set to 'Automatic'. In this mode, operational units are cycled periodically (typically weekly) to distribute wear.

If a high temperature is detected by any unit while Backup & Rotate is active, all connected units are brought into operation to mitigate the temperature rise. In the event of a fault, the MelCOMMS MINI will either bring the next available unit into action or switch on all available units, depending on the "Error Response" setting. The faulty unit(s) will remain in this state until the next changeover cycle.

The device also supports a 'Manual' mode, where the MelCOMMS MINI does not control the indoor units. However, the Fault Relay and High Temp Relay remain operational in this mode.

For testing purposes, a 'Rotation Test Mode' can be activated by powering up the unit with a wire link across inputs IN01, IN02, and IN03. In this mode, the automatic control rotation period is set to 1 minute, and the high temperature alarm is disabled if custom settings are used.

A 'Modbus Slave Test Mode' is also available, activated by powering up the unit with all 8 DIP switches (1-1 to 1-8) in the OFF position. In this mode, the MelCOMMS MINI acts as a Modbus RTU Slave, communicating with fixed settings: Slave ID 1, Baud rate 9600, 8 data bits, and no parity. It will not attempt to communicate with MelcoBEMS MINI (A1M) devices. This mode allows monitoring of MelCOMMS inputs and temporary switching of relay outputs via a Modbus Master PC utility.

Important Technical Specifications:

Power Requirements: 100-240VAC, 0.7A, 50/60Hz.
Operating Temperature: -20°C to +60°C.
Mains Connection: Requires a 6A single gang fused switch in-line with the mains supply, clearly marked as the disconnecting device, and fed via a 6amp type B circuit breaker. The apparatus must be earthed.
Mains Cable Specification: 1.5mm² - 3 core flexible flex (blue, brown, yellow/green), external diameter 8.0mm, BS EN 50525 compliant.
Modbus RS-485 Connection: 3-way screw terminal for Modbus RTU communication with up to 8x MelcoBEMS MINI (A1M) adapters. Requires shielded data cable (A, B, GND connections), with the shield connected to GND at one end only. Connections must be polarized, and the network must be daisy-chained (T-junctions are not permitted).
DIP Switches: 12x DIP switches for configuration, along with 4x digital inputs and 4x configurable inputs (fixed as digital inputs).
Modbus Registers:
- Coil Status Registers (Digital Outputs):
  - Fault Relay Output (Address 0, Modicon 00001): 0 = Relay OFF (de-energised), 1 = Relay ON (energised).
  - High Temp Relay Output (Address 1, Modicon 00002): 0 = Relay OFF (de-energised), 1 = Relay ON (energised).
  - Coil Status Registers can be read using function code 1, written using function code 5 (single coil) or 15 (multiple coils).
- Input Status Registers (Digital Inputs):
  - Digital Input 1-4 state (Addresses 0-3, Modicon 10001-10004): 0 = Input open circuit (no wire link), 1 = Input closed circuit (wire link).
  - Input IN01-IN04 state (Addresses 4-7, Modicon 10005-10008).
  - Input Status Registers can be read using function code 2.
- Input Registers (Analogue Inputs):
  - Firmware Version (Address 0, Modicon 30001): e.g., value 10002 = firmware version 1.0.2.
  - Input Registers can be read using function code 4.
EMC Compliance: 2014/30/EU (EMC Directive), 2014/35/EU (Low Voltage Directive), 2011/65/EU (RoHS Directive).
Dimensions: 255 mm (Front View width) x 185 mm (Side View height) x 105 mm (Top View depth).

Usage Features:

Configuration: The unit's functionality is configured using DIP switches and digital inputs. Changes to configuration settings require a unit restart. Custom settings are applied if links are fitted to both digital input IN03 and IN04, determined by the 12x DIP switches and 4x configurable inputs.
Status Indicators:
- Panel Live LED: Illuminates when the unit is powered.
- Fault LED: Illuminates when a fault is present, such as a communication fault with MelcoBEMS MINI (A1M) units or a fault code (other than 8000 = OK) from an A1M unit.
- Buzzer: Activates concurrently with the Fault LED. Can be muted by pressing the 'Mute' pushbutton, remaining muted until new faults occur after all previous faults are cleared.
- Relay Status LEDs: Four LEDs inside the enclosure on the PCB indicate the status of the relays. LED OFF means de-energised, LED ON means energised. 'Relay 3' is for the Fault Relay, 'Relay 4' for the High Temp Relay.
- RS-485 Comms Status LEDs: Two LEDs next to the DIP switches. One is constantly ON, the other flashes to indicate successful Modbus communication. If both are permanently ON, it indicates no communication.
Error Response Settings: Configurable to either bring the next unit ON or bring all units ON in response to an error.
Rotation Period: Configurable for 1, 3, 5, or 7 days between unit rotations.
Temperature Setpoint: Configurable from 18°C to 25°C.
Mode Selection: Can be set to COOL or AUTO.
High Temperature Alarm: Configurable setpoints from 23°C to 28°C.

Maintenance Features:

Installation Manual: Provides detailed instructions for safe and correct use, including safety precautions, wiring diagrams, and configuration steps.
Troubleshooting Guide: A table outlining common problems, possible causes, and solutions (e.g., checking fused spurs, power supply, fuses, indoor units, wiring, and comms settings).
Warranty: All products manufactured on behalf of Mitsubishi Electric UK are warranted against defective materials for three years from the date of delivery to the original purchaser.
Repair: Users are advised not to repair the unit themselves; an authorised dealer or technician should be consulted for repairs.
EMC Compliance: Designed to reduce interference with radio communications services, with recommendations for using shielded cables and proper installation to maintain EMC classification.
Disposal: Instructions to consult the dealer for proper disposal of the product. Packing materials should be safely disposed of to prevent injury or suffocation risks.