Hardware Information


Our device has been carefully designed to meet our standards of durability and requirements for working in industrial environments.

Its Wi-Fi connectivity complies with the IEEE 802.11 standards and certifications provided by the manufacturer of its microcontroller, the ESP32 manufactured by ESPRESSIF SYSTEMS.


ModbusBox its being manufactured in two variations or models.

ModelSerieSupported SlavesOptionsDescription
MB-A4WA4W: Wi-FiAdvanced model that supports up to 4 slaves connected simultaneously
MB-B1WB1W: Wi-FiBasic model that supports only one slave


The following image shows the internal components, LEDs, connectors and buttons of our ModbusBox. Please observe carefully, we recommend to print this section for a better understanding of any further explanation of the modbus usage and setup.


Figure 1

1RJ45 ConnectorDC power input and Modbus connection
2Programming Mode ButtonUsed to put the device in programming mode (for developers)
3Setup Mode ButtonCombined with reset enters the ModbusBox in setup mode
4Reset ButtonReset the ModbusBox (used combined with 2 and 3)
5Activity LEDMQTT activity white LED
6Wi-Fi ModuleWi-Fi antenna
7Status LEDRGB pixel LED to indicate ModbusBox statuses
8Dev OptionsConnectors (for developers)
9Modbus Interface LEDsIndicate Modbus Tx/Rx activity
10Power LEDGreen LED - indicate power presence
11Power/ModbusSecondary power & modbus connector (for developers)

Table 1


Out ModbusBox features a powerful ESP32-WROOM-32. This microcontroller is capable of functioning reliably in industrial environments, with an operating temperature ranging from –40°C to +125°C. Powered by advanced calibration circuitries, ESP32 can dynamically remove external circuit imperfections and adapt to changes in external conditions.

Engineered for mobile devices, wearable electronics and IoT applications, ESP32 achieves ultra-low power consumption with a combination of several types of proprietary software. ESP32 also includes state-of-the-art features, such as fine-grained clock gating, various power modes and dynamic power scaling.

CPUEspressif ESP32-WROOM-32 2 x Xtensa® 32-bit LX6 microprocessors
RAM520 KB of on-chip SRAM

Table 2

Please refer to the ESP32 datasheet for detailed information

Control Buttons

As you can see in the following image, there are three control buttons located on the PCB. These control buttons allows the user to switch between operation modes and to perform other advanced procedures.


Figure 2

PROG Button

Use this button to put the device in Programming Mode in order to upload a new firmware. To enter into Programming Mode, press and hold Programming button and quick press and release Reset button.

For more information regarding this operational mode, refer to the Programming Mode documentation or the following guide: Uploading firmware in Programming Mode.

SETUP Button

This is a multifunction button that can triggered many actions depending on the state of the device.

For more information regarding this operational mode, refer to the Setup Mode documentation or the following guide: Putting Device in Setup Mode.

RST Button

Used this button to perform a factory reset of the device and restore its defaults state.

For more information regarding this operational mode, refer to the Factory Reset documentation or the following guide: Restoring the device's factory state.

LED Indicators

ModbusBox has 4 LEDs indicators and 1 multicolor LED for system status. This light indicators are very useful to quickly understand the operational status of the ModbusBox. They also helps to troubleshoot any problem with the device operation.


The following table aims to describe every LED of the 4 found on the ModbusBox.

Item number in figure 1Label on PCBIndicationDescriptionColor
10D3DC input voltageWhen ON indicates power voltage has been detected🟢
5D9MQTT activityIt blinks every time an MQTT message is sent or received
9D4Modbus master requestIt blinks when ModbusBox try to communicate with a modbus slave🔵
9D8Modbus response from slaveIts blinks when ModbusBox has received a response from slave🔴

Table 3.1

Status LED

The following table aims to describe the Status LED.

Item number in figure 1Label on PCBIndicationDescriptionColor
7D2System Operational StatusThis RGB LED is color dependent upon device statuses and alarms and special notifications.🔴🟢🔵

Table 3.2

Status LED Colors Patterns

The Status LED, labeled as D2 on the PCB and marked with number 7 in Figure 2, is color dependent upon device statuses and alarms.

The following tables shows the color patterns of different statuses and alarms indications of the Status LED on the ModbusBox.

System Operational Status
StatusAnimationColorHSL Color Code
Setup ModeQuick Fade🟢115
System OKSlow FadeAQUAMARINE174
Connecting to Wi-Fi networkQuick Fade🔵240
Connecting to MQTTQuick Fade🔵240

Table 3.3

Alarms and Notifications
StatusAnimationColorHSL Color Code
No Wi-Fi Connection DetectedQuick Fade🔴0
No MQTT Connection DetectedQuick Fade🟣300
Modbus Failure DetectedQuick Fade🟠60
Device LocatedQuick Fade🟢115

Table 3.4


ModbusBox has only one connector exposed, that is the RJ45 connector used to connect the ModbusBox to the modbus slaves. The 24v needed for ModbusBox and provided by the slaves also comes through this same connector.

There are other connectors located in the ModbusBox PCB that may be used by developers when using the ModbusBox for with their own custom firmware.

Details about those additional connectors will be added to this documentation in the future.