Redraw the circuit,
not your equipment

Instead of adapting your equipment to a general-purpose board, we build the board around your equipment. Communication interfaces, I/O channels, and operating voltage are engineered and populated to your order spec — from a single prototype to full production.

Control MCU
STM32F103 series
Communication
EtherCAT · RS-485 · Wireless
Design Scope
Circuit · Layout · Firmware
Minimum Order
1 ea (prototype)
View LineupRequest a Quote
WIM custom control board hardware

Lineup

Two boards, built to order

Each board keeps a proven base design and changes only the marked sections to your order spec. Because the core stays fixed, moving from prototype to production requires far less re-validation.

EtherCAT Control Board
WIM-CB100

EtherCAT Control Board

An STM32F103-based control board. Communication interfaces, digital I/O channel counts and signal voltages, and relay/PWM/sensor options are all populated to your order spec.

View specs & build an order code →
Regenerative Resistor Board
WIM-RB100

Regenerative Resistor Board

A board that dumps regenerative energy into a resistor once the DC bus voltage crosses a set threshold. Built to your specified turn-on voltage and Schmitt-trigger hysteresis band.

View voltage settings →

WIM-CB100 · EtherCAT Control Board

No dead circuitry, no missing channels

The STM32F103 core and power section stay fixed, while only the communication, I/O, and sensor sections are populated to your order spec. Dropping unused connectors and transceivers cuts board area, unit cost, and power draw together.

WIM-CB100Zone diagram · actual layout varies by order specCOMM — order configINOUTEtherCAT · LAN9252USBRS-485RS-232UARTWIRELESSWi-Fi / BLE / LoRaPOWERDC 24V5V / 3.3VReverse-polarity · TVS protectedCORE — commonSTM32F103 seriesCortex-M3 · 72 MHz64 KB Flash / 20 KB SRAMSWD8 MHz XTALSENSOR — optionalSHT31 temp/humidityVBAT monitor12-bit ADC · I²CI/O — order config (channel count · voltage)DIGITAL IN — 5 / 12 / 24 VRELAY ×4RELAY ×4
WIM-CB100 zone diagram — communication, power, core, sensor, and I/O zones. Actual layout varies by order spec.

Base Specifications

Applied uniformly regardless of order configuration.

MCU
STM32F103 series (LQFP48 / 64)
Core / Clock
ARM Cortex-M3 · 72 MHz
Memory
64 KB Flash / 20 KB SRAM
Input Power
DC 24 V · USB 5 V
Protection
Reverse-polarity · TVS surge · PTC fuse
ADC
12-bit · up to 10 ch
Board
FR-4, 4-layer · 1.6 mm
Size
Determined by order spec
Mounting
M3 mounting holes · optional DIN rail bracket
Connectors
Screw terminal blocks · 2.54 mm pin headers
Debug / Flashing
SWD header · USB DFU bootloader
Dev Environment
STM32CubeIDE · HAL examples provided

Customizable Items

Communication interfaces can be populated in combination, and I/O is specified by channel count and signal voltage. The code is the identifier that goes straight into the order code.

Communication Interfaces COMM

Multiple selections allowed. EtherCAT and wireless modules use significant board area, so combining them may require adjusting I/O channel counts.

EtherCATSlave controller + 2× 100BASE-TX ports (IN/OUT), daisy-chain wiring, CoE support
EC
USBUSB 2.0 Full-Speed device, CDC virtual COM port + DFU firmware flashing
UB
UARTTTL 3.3 V level, up to 3 channels, 2.54 mm pin header
UA
RS-2321-channel transceiver, D-Sub 9-pin or terminal block
232
RS-485Modbus RTU support, 120 Ω termination jumper, isolated transceiver option
485
WirelessOne of Wi-Fi / BLE / LoRa, wired to UART via a dedicated header
WL

Digital I/O I/O

Input signal voltage is specified at order time and populated with isolation circuitry and divider resistors matched to that voltage.

Digital InputPhotocoupler-isolated, 4 / 8 / 16 channels, signal voltage 5 V, 12 V or 24 V
DI
Digital OutputOpen-drain, 4 / 8 / 16 channels, built-in flyback diode
DO
Relay OutputMechanical SPDT contacts, 2 / 4 / 8 channels, status LED, per-channel terminal block
R
PWMUp to 6 channels, 16-bit resolution, for motor driver / dimming control
P

Sensors / Instrumentation SENSOR

Example firmware including value reading and calibration logic is provided.

Temp / HumidityDigital temp/humidity sensor (I²C), onboard or external probe
TH
Battery Voltage / LevelVoltage divider + 12-bit ADC, order-specified range (e.g. 48 V system), includes level estimation
BV

Power Input POWER

Populating both inputs lets you flash firmware over USB while validating field operation at 24 V.

DC 24 VTerminal block input, buck converter generates 5 V / 3.3 V
24
USB 5 VRuns on USB bus power, suited to low-power configs
U5
24 V + USB combinedBoth inputs at once, auto-switched via diode-OR circuit
DU

Build an Order Code

Select the specs you need and an order code is generated automatically. Attach it as-is to your quote request — we confirm the spec against this code during consultation.

Power Input
Communication · multi-select
Digital I/O
Sensors / Instrumentation · multi-select

WIM-RB100 · Regenerative Resistor Board

Cross the set voltage, and regen energy goes to the resistor

A decelerating motor acts like a generator, pushing the DC bus voltage up. RB100 monitors bus voltage continuously, opens a switching element to dump energy into the regen resistor the instant the set turn-on voltage is crossed, and cuts off once voltage drops below the return voltage.

Voltage Settings

Specify the turn-on voltage and hysteresis band, and the thresholds in the graph above update accordingly. The actual settable range is finalized during consultation based on your DC bus system.

WIM-RB100 regenerative resistor board 3D render

Schmitt Trigger Behavior

A single threshold causes repeated switching whenever voltage hovers near the boundary. Spacing the turn-on and turn-off voltages apart with a Schmitt trigger eliminates this chatter.

DC bus voltageTurn-on / dischargingReturn voltage
Threshold Voltage

Discharge starts once this voltage is exceeded.

Larger resists switching chatter; smaller tracks voltage more tightly.

Regen Resistor · Thermal

Used to size the switching element and thermal design.

Options · multi-select

Voltage Settings Specify the turn-on voltage and hysteresis band, and the thresholds in the graph above update accordingly. The actual settable range is finalized during consultation based on your DC bus system.

Base Specifications

Circuit constants and component ratings depend on your system, so items marked TBD are finalized during consultation.

Operation
Bus voltage monitoring → switching discharge
Comparator
Schmitt trigger (hysteresis type)
MCU
None required — analog-only operation
Turn-on Voltage
Order-specified
Return Voltage
Turn-on voltage − hysteresis band
Bus Stabilization
×2 high-capacity electrolytic capacitors
Wiring
2× screw terminal blocks
Status
Onboard status LED
Verification
10 test points (TP1–TP10)
Board
Size / layer count per order spec

Works

We handle design through verification in-house

Circuit design, layout, panelization, firmware flashing, and functional verification all happen in-house — so when something goes wrong, we can trace it all the way back to the circuit.

Panelization
PanelizationPanelizing the same design together lowers both assembly cost and unit price. Pictured: 5 STM32F103 boards configured with USB · dual EtherCAT ports · ADC · PWM.
Firmware Flashing & Functional Verification
Firmware Flashing & Functional VerificationFirmware is flashed over SWD, and EtherCAT communication, potentiometer ADC input, and PWM output are all verified in live operation before shipping.

Applications

Where it's used

AMR / Transport Robots

Connects to the host controller over EtherCAT, drives peripherals via relay, and continuously monitors 48 V battery voltage.

EtherCAT Slave I/O Nodes

Distributed I/O bridging a master controller to field sensors and actuators — daisy-chain wiring cuts down control-panel cabling.

Servo / Motor Deceleration

The regen resistor board catches the DC bus voltage spike during deceleration, preventing drive overvoltage trips.

Equipment Control / Interlocks

Isolated inputs read proximity and limit switches; relay contacts drive solenoids and indicator lamps.

Remote Telemetry

Periodically collects temperature, humidity, and voltage and sends it upstream over RS-485 Modbus or wireless.

Legacy Equipment Retrofits

Used as a gateway to add RS-485 or EtherCAT to aging equipment that only supports RS-232.

Process

Production Process

The standard timeline from inquiry to production. Varies with option configuration and quantity.

01

Spec Consultation

We confirm field signal types, communication environment, system voltage, and installation conditions.

1–2 days
02

Spec Finalization & Quote

We finalize the order code and present the circuit configuration and unit price.

2–3 days
03

Prototyping

Circuit design, layout, board fabrication, assembly, and firmware flashing.

2–3 weeks
04

Field Verification

We deploy to your actual equipment to verify signals and communication, and tune constants and firmware.

1–2 weeks
05

Production

Repeat production from the finalized drawings.

3–4 weeks

Inquiry

Request a Quote

Leave your requirements along with the order code you built, and our engineer will get back to you within 1 business day.