INDUSTRIAL HMI · HMI700

7-inch industrial equipment HMI PCBA

Bring equipment data, parameter viewing and service diagnostics onto one capacitive touchscreen. HMI700 connects to a PLC or controller through isolated RS485, receives classic CAN diagnostics, and integrates display, power, touch and local settings storage on a 160 × 100 mm board.

HMI700 industrial HMI PCBA 3D assembly view
Package assembly view generated from the PCB layout
7″
800 × 480 · capacitive touch
24 V
18–30 V DC
2 isolated buses
RS485 + CAN
160 × 100
mm · 4 PCB layers

Applications

A local operator interface for indoor equipment panels and control cabinets. The HMI reads controller data; equipment interlocks and actuation belong to the PLC, dedicated controller and safety circuits. Units, ranges, alarm wording and register addresses are mapped to the equipment protocol.

Packaging & assembly machines

View production counts, running states and fault codes from the PLC. A diagnostics page separates communication timeouts and exception responses from equipment data, giving operators a single panel for the machine.

Heating & process equipment

Display controller-supplied temperature, level, pressure and flow registers, with a visible distinction between current values and stale data. Sensor acquisition, PID, contactors and independent thermal protection remain in the equipment controller.

Pump sets & water treatment

Present pump states, totalized flow, operating hours and fault information. Use RS485 for the field controller and map parameter names, engineering units and permitted commands to its register table.

Test stands & fixtures

Organize counts, step codes and result codes into local pages. Back, confirm and next-page buttons support menu navigation; USB status queries provide a diagnostic connection to the workstation.

Equipment service & retrofit

Add local visualization to an existing 24V cabinet while retaining the PLC control architecture. Adapt the RS485 address, baud rate, panel cutout and harness length to the installation.

Industrial CAN diagnostics

Receive classic CAN status frames and show reception counters and communication errors. The included receive setup uses 500kbit/s and standard ID 0x180; field decoding can be adapted to the equipment protocol.

System architecture

The display module handles frame storage and graphics output. The main board handles page logic, data parsing and power. Each field communication interface has its own isolated supply; the display and MCU share the logic domain.

01

24V input

Fuse / reverse-polarity diode / TVS

02

5V + 3.3V

LMR36520 / TSR 2-2433

03

STM32F407

Pages / communication / watchdog

04

7-inch touch

RA8875 display / GT911 touch

05

Field interfaces

Isolated RS485 / isolated CAN

06

Local service

USB CDC / SWD / SPI Flash

24V → 5V → 3.3V → MCU / LCD · MCU ↔ RS485 / CAN · MCU ↔ USB / SPI Flash

Circuit & selections

ModuleSelectionDesign detail
MCUSTM32F407VGT6168MHz Cortex-M4; FSMC drives the 16-bit display bus, I²C reads touch and SPI connects settings storage.
Display & touchWaveshare 7inch Capacitive Touch LCD (C), GT911800×480; RA8875 display controller and frame storage; 34-pin 2×17 host connection.
24V input & 5VLMR36520ADDAR + XAL6060-153MEC18–30V design input range; 15µH inductor and ≤1.7A continuous 5V design budget. Fuse, series diode and TVS form the input protection path.
Input capacitance5×2.2µF/100V X7R + 220nF/100V11µF nominal; effective capacitance is evaluated for 30V DC bias, tolerance, temperature and aging. The local smaller capacitor provides high-frequency bypass.
3.3V branchTRACO TSR 2-2433Converts 5V for the MCU and display; ≤1.4A continuous system design budget, allocated using full-brightness and startup demand.
Isolated RS485TI ISO1410DWR + TRACO TMR 1-0511Separate logic and bus-side grounds; SM712 at A/B, with 100nF and 10µF local decoupling. JP2 inserts a 120Ω termination.
Isolated CANTI ISO1042DWVR + a separate TMR 1-0511Classic CAN 2.0; CAN_H/CAN_L TVS protection and JP3 120Ω termination. Its bus-side supply is independent of RS485.
Settings storageWinbond W25Q64JVSSIQ8MB SPI Flash; two independent 4KiB sectors alternate local settings records with CRC32, sequence numbers and a commit marker.
USB serviceUSB-C / USB 2.0 Full Speed / USBLC6-2SC6Self-powered CDC device; VBUS sensing is separate from board 5V. D+/D− have ESD and series damping; STATUS returns diagnostics.
PCB & assembly160×100mm / 4 layers / 115 parts103 SMT plus 12 through-hole components; two optional bias resistors are unpopulated. Four M3 hole centers: (5,5), (155,5), (5,95), (155,95)mm.

Interfaces & wiring

PortPinoutConnection
J1 · power1=+24V; 2=GND; 3=CHASSISNominal 24V DC; CHASSIS is the functional shield reference.
J2 · display34 pins, 2×17, 2.54mm, straight-through3.3V; D0..D15, CS, RS, WR, RD, RESET, WAIT and touch INT/SDA/SCL.
J5 · RS4851=A; 2=B; 3=ISO485_GND; 4=CHASSISA is non-inverting. Some controllers reverse A/B naming; verify polarity.
J6 · CAN1=CAN_H; 2=CAN_L; 3=ISO_CAN_GND; 4=CHASSISTerminate the two bus ends; do not add termination at every node.
J4 · SWD1=VTref; 2=SWDIO; 3=SWCLK; 4=GND; 5=NRSTVTref senses board 3.3V; avoid competing debugger and board supplies.
J3 · USB-CUSB 2.0 FS self-powered deviceConnect a data cable to the PC. Equipment power comes from the 24V input.

J2 pins 3..18 carry D0..D15; 19..23 are CS/RS/WR/RD/RESET; 25 and 33 are 3.3V; 2, 26 and 34 are logic ground; 29 is WAIT; 30..32 are touch INT/SDA/SCL. Pin 26 selects 16-bit 8080 mode. Pins 1, 24, 27 and 28 are reserved. The module’s internal 40-pin flex is not the main-board host connection.

Firmware & interaction

The firmware uses STM32Cube and PlatformIO. Status, settings and diagnostics/alarm pages use GT911 single-point interaction and the module’s built-in Western character set. Equipment-specific fonts, units, trends and alarm history can be added for the application.

  1. Initialize clocks, FSMC, I²C, SPI, UART, CAN, USB and the independent watchdog.
  2. Send Modbus RTU FC03 reads as a master: address 1, 115200/8N1, eight registers every 500ms by default.
  3. Validate CRC, length, address and function code; handle exceptions, timeouts and UART errors in diagnostics.
  4. Refresh the status page. Show empty values before data arrives and mark stale values after timeout.
  5. Allow a 250–2000ms polling interval, stored in SPI Flash with alternating sectors and a commit marker.
  6. Retry failed touch communication every second; CAN counters and USB STATUS provide service diagnostics.

The application reads the remote device by default. FC06 frame generation and response validation functions are included; device writes require the actual protocol and operator permissions. CANopen, J1939 and CAN FD require separate adaptation. ST-Link/SWD downloads firmware; USB CDC provides status queries.

USB CDC > STATUS
Modbus RTU > FC03 · 8 registers · 115200 / 8N1
CAN > 500 kbit/s · standard ID 0x180
SWD > pio run -t upload

Installation & accessories

The system selection separates display, external 24V power, harnesses, installation parts and service tools. Download 23 accessory lines and 17 harness-material lines; the complete package also includes five mechanical DXF/SVG designs.

AccessorySelection / typeIntegration
Display moduleWaveshare SKU8964, GT911 versionMatch the 34-pin direction, full-brightness current and glass support locations.
Cabinet supplyMean Well HDR-30-2424V DIN-rail supply; mains wiring belongs to the cabinet design.
Display harness34-pin, 1:1 straight-throughMark pin 1 with the red edge at both ends. Use only 3.3V and keep it short, away from power switching wiring.
Field harnessesRS485 / CAN / shield referenceKeep each isolated ground and shield reference distinct; coordinate shielding with the machine grounding arrangement.
Mounting & structureM3 standoffs, screws, backplate, bezel, clamps and insulating/contact padsSet the cutout and clamping from glass, visible area, PCB thickness, cable exit and support geometry.
Service toolsGenuine ST-LINK/V2, USB data cable and bus adaptersMatch VTref, SWD and isolated bus wiring. Shared service tools are separate from per-machine material.

The display and MCU share logic ground. RS485 and CAN each use their own isolated bus ground; avoid shorting all three domains together. Implement emergency stops, drive permissions and independent protection in the equipment architecture. The touchscreen provides operator interaction and information.

Technical downloads

Download without registration. The complete package contains KiCad schematics and PCB, footprint libraries, BOM, Gerber/drill/placement files, firmware source and ELF/BIN, accessories, harnesses, mechanical drawings, integration documents and 3D assets. Category packages support hardware, firmware and mechanical work; original engineering records are retained in the complete archive.

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