EQXHI10 Datasheet

#Overview

The EQXHI10 is a 10-channel isolated high-voltage input expansion module designed to add AC and DC voltage-presence sensing to the EQSP32 Industrial IoT controller. Each of the ten galvanically isolated channels detects the presence of field voltage over a 5 to 380 V peak range, allowing mains-level and control-level circuits to be monitored directly, without interposing relays or external signal conditioners. The module reports whether voltage is present, not its magnitude.

The ten inputs are arranged in two independently isolated groups of five, each with its own common terminal. Inputs IN1 to IN5 reference the COM 1-5 terminal and inputs IN6 to IN10 reference the COM 6-10 terminal, allowing two separate circuits, phases, or reference potentials to be monitored from the same module. Isolation is provided per group, with an isolation component rating of 3750 Vrms, separating each group from the controller electronics and from the other group.

Beyond simple presence detection, the EQXHI measures the frequency of each input and derives a live signal-quality value based on frequency stability and deviation from the expected frequency. Each input group can be configured with an expected frequency, an allowed deviation, and an assertion and recovery delay, so the application can distinguish an input that is off from an input that is on but unhealthy. Input states are debounced on the module, requiring no additional filtering in the application code.

Each energised channel draws approximately 1 mA through a constant-current input stage, the same at 24 V as at 380 V. Like all EQX expansion modules, the EQXHI is housed in a compact DIN-rail mount enclosure and is powered directly through the EQSP32 board-to-board expansion connector, requiring no external power supply.

The module is automatically detected and indexed by the EQSP32 upon power-up, enabling true plug-and-play integration. The expansion connectors carry the internal bus and supply rails, so chained modules address themselves with no jumpers or manual configuration. Firmware updates are performed through the front-facing USB-C port.

Integration is further simplified through the EQSP32 library and EQ-AI generative AI model, allowing users to read input states, signal quality and frequency-deviation status with minimal development effort. This makes the EQXHI an ideal solution for panel state monitoring, mains and phase presence detection, and the retrofit of existing control panels into modern IIoT systems.

#Key Features

• 10× galvanically isolated high-voltage input channels
• Isolation per input group, 3750 Vrms isolation component rating
• AC, DC and pulsed (PWM) voltage presence detection
• 5 to 380 V peak voltage presence detection range
• 380 V peak maximum continuous input voltage
• Presence detection only, voltage magnitude is not measured
• Constant-current input stage, approximately 1 mA per energised channel
• Two independent input groups with dedicated common terminals (IN1–IN5 and IN6–IN10)
• Detection in under 2 ms with a 40 ms release hold
• On-module input debouncing, no filtering required in the application code
• State, rising edge, falling edge and toggle trigger modes
• Per-input live signal quality reporting
• Configurable expected frequency, allowed deviation and assertion/recovery delay per input group
• Per-input frequency-deviation status reporting
• Reverse-polarity blocking on every input
• Automatic addressing on the expansion chain, no jumpers or manual configuration
• Automatic module detection and indexing by EQSP32
• Powered directly through the EQSP32 board-to-board expansion connector
• Front-facing USB-C port for firmware updates
• LED indicators for power and module status
• Up to 15 EQXHI on each EQSP32 controller
• Generative AI coding assistant trained with EQSP32 Library and EQXHI features
• Compact, 2SU-wide (36 mm), DIN-rail mount enclosure with 2× 6-position 5.08 mm screw terminal blocks
• IP20 protection
• −20 °C to +55 °C operating ambient temperature

#Applications

• Contactor, relay and motor-starter feedback monitoring
• Mains, phase and supply presence detection
• Pump, fan and motor run-status monitoring
• Lighting, heating and load circuit state monitoring
• Safety chain, interlock and emergency-stop circuit supervision
• Generator, UPS and mains changeover detection
• Machine state and process step monitoring
• Building automation and HVAC panel monitoring
• Retrofit of legacy relay-logic panels into modern IIoT systems
• Distributed state monitoring using EQSP32 expansion architecture

#Block Diagram

#System Specifications

#Electrical Specifications

#Input Ratings

#Connecting EQXHI

To install the EQXHI high-voltage input expansion module, mount it next to the EQSP32 controller on the DIN rail and slide it until the board-to-board connector is fully engaged with the expansion interface. The module is powered entirely through this connector and does not require any external power supply.

When adding or removing expansion modules, it is recommended to disconnect system power beforehand. After power is applied, the EQSP32 automatically detects and indexes all connected expansion modules, including the EQXHI, enabling immediate plug-and-play operation without additional configuration.

For safety and ease of installation, it is strongly recommended that a main circuit breaker is used to fully isolate the system’s AC/DC power source and the monitored circuits when installing, removing, or rearranging expansion modules. The EQXHI inputs contain no integral surge suppression, so external surge protection should be provided according to the overvoltage category of the installation.

#Visual Indications

When the EQXHI module is connected to the EQSP32 controller and the system is powered on, the POWER LED illuminates solid green, indicating that the module is properly powered.

If the STATUS LED remains solid red after the automatic detection process, this indicates that the EQXHI module is not communicating correctly with the EQSP32.

During normal operation, when data exchange occurs between the EQSP32 controller and the EQXHI module, the STATUS LED will flash to indicate active communication and input state updates.

#Power LED (green)

#Status LED (red)

#Pinout

X1

Screw terminal connector 1

USB-C

Firmware update port

X2

Screw terminal connector 2

The EQXHI10 provides ten galvanically isolated high-voltage input channels arranged across two 6-position, 5.08 mm screw-terminal blocks. Each block carries five inputs and a dedicated common terminal, so the two groups can be referenced to different circuits, phases, or potentials.

#X1 — Screw Terminal Connector 1 (Inputs IN1 to IN5)

The X1 screw terminal connector provides access to the first group of high-voltage input channels on the EQXHI module. It is used to connect inputs IN1 through IN5, all referenced to the COM 1-5 common terminal provided on the same connector.

Each input channel detects the presence of field voltage on:

• An AC or pulsed circuit within the detection range, or
• A DC circuit within the detection range, with INx as the positive conductor.

#X2 — Screw Terminal Connector 2 (Inputs IN6 to IN10)

The X2 screw terminal connector provides access to the second group of high-voltage input channels on the EQXHI module. It supports inputs IN6 through IN10, with identical electrical behavior to X1, all referenced to the COM 6-10 common terminal.

Because each group has its own common terminal, X1 and X2 can be wired to different circuits, phases, or reference potentials within the same panel. Both connectors are 6-position, 5.08 mm screw terminal blocks.

#USB-C — Firmware Update and Maintenance Port

The USB-C connector on the EQXHI module is used exclusively for:

• Firmware updates
• Maintenance and recovery operations

Normal operation requires the module to be powered through the EQSP32 board-to-board expansion connector.

#Power Distribution

The EQXHI expansion module is powered through the EQSP32 board-to-board expansion connector and does not require any external power supply. The EQSP32 supplies the module’s internal system, the control unit and its peripherals. The isolated input detection circuits are powered by the monitored circuit itself, drawing approximately 1 mA per energised input, and are galvanically isolated from the internal system.

The expansion connectors carry the internal bus together with the supply rails and an address chain, and pass all of them through to the next module, so boards simply chain together and assign their own addresses with no jumpers or manual configuration.

The front-facing USB-C port is provided exclusively for firmware updates and maintenance operations. While the module responds when powered via USB, normal operation is intended to occur only when the EQXHI is powered through the EQSP32 expansion connector.

Because power is delivered automatically through the slide-to-connect mechanical interface, the EQXHI becomes operational immediately upon docking and the EQSP32 is powered up—no external wiring, terminals, or additional power connections are required.

#Mechanical Dimensions

All dimensions are measured in mm with a ±0.1 tolerance.

#High-Voltage Inputs (IN)

The EQXHI provides ten galvanically isolated high-voltage input channels that detect the presence of AC, DC or pulsed field voltage. All channels operate as fixed digital inputs and require no mode configuration. The module reports presence only; it does not measure the magnitude of the applied voltage. In addition to the logic state, each channel reports a live signal-quality value derived from the measured input frequency, so a healthy energised circuit can be distinguished from an unhealthy one.

#Equivalent INx Circuit

#Input Overview

All INx terminals on the X1 and X2 connectors operate as fixed digital inputs and no pinMode() configuration is required.

Each input is referenced to the common terminal of its own group: IN1 to IN5 to COM 1-5, and IN6 to IN10 to COM 6-10.

Each input (INx pins) on the X1 and X2 terminals shares a common architecture: a constant-current input stage drawing approximately 1 mA, a series element that blocks reverse polarity, galvanic isolation from the controller electronics, and on-module debouncing of the detected state.

In DIN operation, each channel reports whether field voltage is present on the input. The state is debounced on the module before it is reported to the EQSP32, so no additional filtering is needed in the application code.

The QUALITY value reports how stable the measured input frequency is and how far it deviates from the expected frequency configured for the input group. Frequency supervision is optional and is disabled by default. While supervision is disabled, an energised input reports NOT_MONITORED once its signal has been classified, for DC and AC alike.

#Voltage Presence Detection (DIN)

In voltage presence detection, the selected INx channel reports whether field voltage is present between the INx terminal and the common terminal of its group.

Voltage presence is detected from 3 V up to 380 V peak, for AC, DC and pulsed circuits; typical applications use 5 V and above. The maximum continuous input voltage is also 380 V peak. The detected state asserts in under 2 ms and is held for 40 ms after the voltage was last seen, so contact bounce and the gaps of AC and pulsed signals do not appear in the application code. Any detected voltage pulse, however short, reports the input as present for at least 40 ms.

Connect the monitored circuit between the desired INx terminal and the COM terminal of the same group, as shown in the wiring diagram. For DC circuits, INx must be the positive conductor and COM the return; a reverse-polarity connection is blocked and reads the same as no voltage. No additional external components are required.

#Input State Representation

In voltage presence detection, the input state is reported as a logic value: 1 when field voltage is present on the input and 0 when it is not.

Example: a reported value of 1 returned by inState = eqsp32.readPin( EQXHI(1, EQXHI_IN_3) ); corresponds to the state measured on channel IN3 of the first EQXHI module in the expansion chain:

• 1 – field voltage present on IN3

Trigger modes may be used to detect events instead of polling the state, for example ON_RISING to catch the moment an input becomes energised:

• turnedOn = eqsp32.readPin( EQXHI(1, EQXHI_IN_3), ON_RISING )

#Signal Quality and Frequency Supervision

In addition to the input state, the EQXHI measures the frequency of each input and reports a live signal-quality value based on frequency stability and on the deviation from the expected frequency configured for the input group. The measured frequency of each input can also be read directly, in 0.1 Hz.

Frequency supervision is configured per input group. Inputs IN1 to IN5 form the first group and inputs IN6 to IN10 the second, so a single configuration call applies to all five inputs of that group.

An expected frequency of 0 declares a DC circuit, while a value between 25 and 1000 Hz supervises an AC line. The allowed deviation defines how far the measured frequency may drift before a fault is flagged, and the trigger delay defines how long the deviation must persist before the fault is asserted. The same delay is applied on recovery. A DC input is recognised after about 45 ms of continuous voltage; an AC input is measured after three full periods (60 ms at 50 Hz, 120 ms at 25 Hz) and reports ACQUIRING until then.

#Configuring an Input Group

The expected frequency, allowed deviation and trigger delay are applied with a single call per input group. Either EQXHI_COM_GROUP_1 / EQXHI_COM_GROUP_2 or any input pin belonging to the group may be used. Setting the allowed deviation to 0 disables monitoring for that group.

Example: eqsp32.configFREQ( EQXHI(1, EQXHI_COM_GROUP_1), 50, 2, 500 ); sets a 50 Hz target with ±2 Hz allowed deviation and a 500 ms trigger delay for inputs IN1 to IN5 of the first EQXHI module. The diagram below shows how input IN3 responds when its frequency leaves the band and returns.

#Signal Quality Reporting

Each input reports a quality value that reflects how stable the measured frequency is and how closely it matches the expected frequency of its group. A separate delayed-error flag indicates a persistent frequency-deviation fault. The input state, the quality value and the delayed-error flag are separate pieces of information and should be evaluated together; together they distinguish an input that is off from an input that is on but unhealthy.

#Quality Value Representation

The signal quality of each input is read from the corresponding QUALITY channel of the module.

Example: a reported value returned by q = eqsp32.readPin( EQXHI(1, EQXHI_QUALITY_3) ); corresponds to the signal quality measured on channel IN3 of the first EQXHI module in the expansion chain:

• EQXHI_FREQ_QUALITY_GOOD – input energised, frequency within tolerance

A delayed-error flag (0x80) may be present in the same value, indicating a persistent frequency-deviation fault on that input:

• EQXHI_FREQ_QUALITY_BAD | 0x80 – persistent frequency deviation

The delayed-error flag is only meaningful while voltage is present. When an input loses voltage, or is still acquiring after it returns, the flag keeps its last value. It clears once the input has been back within tolerance for the trigger delay, or when the group is reconfigured. Read the input state first: while it is 0, no voltage is present and the flag can be ignored.

#Boot Button & Firmware Update

#Boot Button

The Boot button is used exclusively to place the EQXHI module into firmware update (maintenance) mode. It is not required for normal operation.

To enter firmware update mode:

1. Press and hold the Boot button
2. While holding the button, power the module by connecting the front-facing USB-C port to a PC host.
3. Release the Boot button after power is applied.

The module will enter maintenance mode and appear to the host computer as a USB mass-storage device.

#Firmware Update Procedure

Firmware updates for the EQXHI are performed through the front-facing USB-C port like copying a file into a storage device.

To update the firmware:

1. Download the latest EQXHI firmware from erqos.com website.
2. Ensure the module is in maintenance mode (see Boot Button section above).
3. Locate the removable storage device labeled RPI-RP2 on the host computer.
4. Copy (or drag and drop) the provided .uf2 firmware file onto the device.
5. The firmware update will start automatically.

Once the update is complete, the module will reboot. Power-cycle the system and ensure the EQXHI is powered through the EQSP32 board-to-board expansion connector to resume normal operation and allow automatic module detection and indexing.