Tutorials2026-03-22

Modbus DC/DC Converter Tutorial: Connecting the DCP48M to a Windows PC

Dr. Michael Heidinger
CEO, Digital Power Systems

Introduction

This tutorial provides a step-by-step guide for establishing a Modbus connection between the DCP48M DC/DC converter and a Windows PC using a USB-to-RS485 adapter.

Required Material

DCP48M DC/DC converter
Windows PC
USB-to-RS485 adapter (recommended: Waveshare FTDI USB-to-RS485). A programming kit is also available directly from DPS.

Hardware Wiring

DCP48M connected to a Windows PC via USB-to-RS485 adapter.

Modbus wiring diagram — Connect terminal A to A and B to B. Optional ground via the "-" terminal on the 2-pin connector.

Establishing the Modbus Connection

We use the Radizio! Modbus Master Simulator (RMMS) software for this tutorial.

Step 0: Ensure Power and Connection

Make sure the DCP48M is powered on and the USB-to-RS485 adapter is connected to both the PC and the DCP48M.

Step 1: Open RMMS

Launch the RMMS.exe application.

Step 2: Load Configuration

Go to File → Open configuration file and load the DCP48M configuration file.

Step 3: Connection Settings

RMMS Connection menu — Navigate to Connection → Settings.

Go to Connection → Settings.

Step 4: Configure COM Port

RMMS connection settings — Match the connection settings. Find the COM port via Windows Device Manager.

Match the recommended connection values. Find your COM port number via Windows Device Manager → Ports (COM & LPT).

Step 5: Connect

RMMS connection established with live data — Successful connection: the Systick counter should increment by approximately 10 per second.

Go to Connection → Connect. If the connection is successful, the Systick counter should increment by approximately 10 per second.

Frequently Asked Questions

How do I check if the DCP48M is powered? The RGB LED on the board should be illuminated.
How do I verify the connection? The Systick counter in RMMS should be counting up.
How do I save parameter changes? After modifying parameters, trigger a save command via the Modbus registers.
How do I perform a factory reset? Consult the DCP48M datasheet for the factory reset procedure via Modbus.

Modifying Control Parameters

⚠ Warning: Modifying control parameters may void the warranty. Proceed with caution.

Basic Parameters

Output Voltage (Uset): Value in mV
Output Current (Iset): Value in mA
On/Off: 1 = On, 0 = Off

Modbus Parameters

Modbus ID: Device address on the bus
Baud Rate: Communication speed (changing this saves all parameters)

Control Loop Parameters

Voltage Control: KUp (proportional), KUi (integral), Deadband
Current Control: KIp (proportional), KIi (integral), Deadband

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