D3J0108 Modbus
8-channel fully isolated Modbus-RTU/RS-485 digital input module for machine and cabinet status monitoring.
🔍 Click to enlarge · 1/3Technical Specifications
| Order Code | D3J0108 (default no wireless, RS-485 only) |
|---|---|
| Product ID / Default Slave Address | 0x3108 |
| Inputs | 8-channel fully isolated digital input (plus 2 analog inputs, 1 x 5V/100mA power output) |
| Outputs | None (pure input type, no relay/transistor output) |
| Communication Interface | RS-485 (Modbus-RTU, default 9600/8-Even-1); optional 2.4GHz wireless |
| Supply Voltage | DC 11-28V |
| Physical Interface | RS-485 half-duplex, differential twisted pair A/B; plus USB port; optional 2.4GHz wireless Modbus-OTA |
| Communication Protocol | Modbus-RTU (primary); plus Modbus-ASCII, AT commands; wireless Modbus-OTA |
| Default Baud Rate | 9600 bps |
| Default Data Format | 8 data bits, even parity, 1 stop bit |
| Default Slave Address | 0x02 |
| Optional Baud Rates | 300 / 600 / 1200 / 1800 / 2400 / 4800 / 7200 / 9600 / 14400 / 19200 / 28800 / 38400 / 56000 / 57600 / 76800 / 115200 bps |
| Optional Parity | None / Odd / Even (default Even) |
| Optional Stop Bits | 1 (default) / 1.5 / 2 |
| Slave Address Range | 1-247 (0x01-0xF7) |
| USB Mode Address | Fixed at 0x01 when USB is connected; RS-485 then switches to master mode |
| Input Threshold | Approx. 3V |
| Input Counting | Per-channel DINnCNT, increments on rising edge; pulse frequency up to 5Hz, rolls over at 65535, clearable by write |
| Input Filtering | Per-channel DINnFLT, 1-65535ms adjustable (0=off), savable through power loss via MODESAVE="MS" |
| Supply Ripple | < 1Vp-p |
| Supply Current | < 1500mA |
| Communication Port Stress | DC 0-5V |
| Input Port Stress | DC 0-30V |
| Communication Isolation Voltage | < 250V |
| Input Isolation Voltage | < 250V |
| Operating Temperature | -20 to 60C |
| Max Supply Voltage (absolute) | DC 28V |
| One-Time Fuse | DC 250V, 3000mA, slow-blow |
| Max Communication Port Stress (absolute) | DC 50V |
| Max Input Port Stress (absolute) | DC 50V |
| Max Communication Isolation Voltage (absolute) | DC 1000V, 60 seconds (type test only) |
| Max Input Isolation Voltage (absolute) | DC 1000V, 60 seconds (type test only) |
| Storage Temperature | -40 to 85C |
| ESD Immunity | 4kV to all terminals -> normal operation (Criterion A) |
| EFT Immunity | 2kV/5kHz/2min -> normal (A); 4kV/5kHz/2min -> no permanent damage (C) |
| Surge Immunity | 1kV, all terminals to ground -> no permanent damage (C) |
| Creepage Distance | > 6.5mm measured (requirement > 6mm, pollution degree 3) |
| Clearance | > 2.2mm measured (requirement > 2mm, pollution degree 3) |
| Input Response Time | Typical 20ms |
| Serial Command Reply Time | Max 25ms |
| Module Dimensions (L x W x H) | 72 x 88 x 59mm (tolerance +/-5%) |
| Terminal Pitch | 5.08mm |
Overview
The D3J0108 is an 8-channel fully isolated digital input module built around a dedicated ASIC and communicating over RS-485 using the Modbus-RTU protocol. It is a pure input device with no relay or transistor outputs, designed for machine builders and panel integrators who need to read switch and sensor status from a single machine or a small-to-medium control cabinet onto one board.
The module reads all 8 channels over RS-485 at a default of 9600 bps, 8 data bits, even parity, 1 stop bit, and slave address 0x02, with a supported address range of 1-247. It also includes a USB port for configuration and USB-to-serial operation, per-channel edge counting up to 5Hz and adjustable input filtering from 1 to 65535ms, plus 2 auxiliary analog input channels and a 5V/100mA sensor power output.
Features & Benefits
Eight Isolated Inputs - Sized for One Machine or One Cabinet
8 fully isolated digital inputs collect and report status only; there are no outputs to wire or configure. Eight channels match the real point count of a typical machine or small-to-medium cabinet, so you do not stack two 4-channel boards to reach 6 points and you do not pay for a dozen idle channels on a 16/28-channel board. The 8-channel housing is only 72mm long, against 107mm for the 16-channel and 158mm for the 28-channel version.
2kV EFT Immunity - Double the Industrial Requirement
IEC61000-6-2-2016 asks for 1kV EFT in industrial environments; the D3J0108 rides through 2kV/5kHz/2min with normal operation (Criterion A) and survives 4kV without permanent damage (Criterion C). It also takes 4kV ESD on any terminal with no interruption and 1kV surge to ground without permanent damage. That margin is what keeps a status board from dropping offline every time a contactor beside it slams shut.
Full Isolation Plus Protection on Every Port
Digital inputs and the RS-485 port are electrically isolated from internal logic - under 250V working, verified to DC 1000V for 60 seconds as a type test - so a field-side fault cannot walk back up the bus into your PLC. The supply is protected against reverse connection, over-current, surge and automotive load-dump, the inputs and comms port carry reverse-polarity and surge protection of their own, and a DC 250V / 3000mA slow-blow fuse backs the whole thing up.
Takes Field Signals Directly - No Signal Conditioning
Inputs accept DC 0-30V with an approximately 3V threshold, so 12V and 24V field contacts, proximity switches and photoelectric sensors land straight on the terminals with no interposing relays or level shifters. Absolute maximum input stress is DC 50V, real headroom over the 30V working range, so a wiring mistake on site is a bad day rather than a dead board.
Per-Channel Filtering and Counting - Debounce Off Your PLC
Every one of the 8 channels carries its own DINnFLT anti-chatter filter, adjustable from 1 to 65535ms (0 disables it), and its own DINnCNT rising-edge counter that accepts pulses up to 5Hz and rolls over at 65535. Filter settings survive a power cut once MODESAVE is written as "MS". Contact bounce is cleaned up inside the module, so you are not spending PLC scan time and ladder rungs on a debounce timer for every input.
Drop-In Modbus - Nothing to Develop
The module ships at 9600 bps, 8 data bits, even parity, 1 stop bit, slave address 0x02, and answers standard function codes including 0x02 read discrete inputs, 0x04, 0x03, 0x06, 0x10, 0x16, 0x17 and 0x11 report device ID. Serial reply time is at most 25ms and input response time is typically 20ms. With slave addresses 1-247 and baud rates up to 115200 bps, many modules share one twisted pair and connect straight to a PLC, HMI, SCADA or configuration software.
Four Ways In - RS-485, USB, ASCII and Optional Wireless
Beyond RS-485 there is a USB port that doubles as a USB-to-serial adapter: plug it in and the module sits at fixed address 0x01 while its RS-485 port turns into a master, so an engineer configures or bench-tests the board from a laptop without buying a separate converter. Modbus-ASCII eases touchscreen and PLC integration, AT commands stand up a simple application in minutes, and an optional 2.4GHz self-organising Modbus-OTA link removes the trunk wiring entirely.
Details That Show the Design Was Taken Seriously
Creepage on the high-voltage side is slotted to a measured 6.5mm against a 6mm requirement, and clearance measures 2.2mm against 2mm, both at pollution degree 3. Sensitive registers sit behind SAFELCK: you write ASCII "UL" to unlock, it re-locks after a single write, and any CRC error on the bus re-locks it too, so line noise cannot silently rewrite a slave address. Two bonus analog inputs (1mV per bit, approx. 10-bit, typ. 3% accuracy) and a 5V/100mA sensor supply ride along inside the housing, and an input-reinforced "XS" variant is available for the worst EFT sites.
Applications
Models & Ordering Information
D3J0108
How to Select
- Choose the 8-channel D3J0108 when a single machine or a small-to-medium cabinet has 5-8 input points, which balances density and cost against both the 4-channel and the 16/28-channel versions.
- If points are few and scattered and near-device deployment is preferred, the 4-channel D3J0104 saves wiring.
- If a single location's point count grows past a dozen, use the 16-channel D3J0116.
- For cabinets consolidating dozens of points, use the 28-channel D3J0128.
- Choose the optional 2.4GHz wireless version where wiring is inconvenient.
- For applications with frequent strong EFT or inductive loads, order the input-reinforced variant (order code suffix "XS").
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When NOT to specify the D3J0108 — and what to use instead
The application needs to switch something - a contactor, indicator, valve, or pump - not just report a signal.
Why not: D3J0108's own spec lists its outputs as 'None - pure input module, no relay or transistor output'; there is no output register, relay, or transistor stage on the board at all.
Use instead: D3J0304 (4 isolated inputs + 2 outputs) for combined input+output on one board, or D3J0208 (8-channel output) if only outputs are needed.
Only 2-3 signals exist at a given point, and they are physically far from other signal groups.
Why not: D3J0108's spec fixes it at '8-channel fully isolated digital input' on one 72mm-long board and one slave address - using it for 2-3 far-flung points means wiring long runs back to one 8-channel board instead of placing a smaller module at each point.
Use instead: D3J0104 (4 inputs), deployed near each signal group instead of consolidating onto one D3J0108.
A single cabinet or machine actually has more than 8 input points.
Why not: D3J0108's channel count is fixed at 8 in its own specification - there is no field or ordering option to extend it further.
Use instead: D3J0116 (16 inputs) or D3J0128 (28 inputs).
The signal is part of a machine safety function - an emergency-stop circuit, a safety door interlock, a light-curtain OSSD, or a two-hand control input.
Why not: D3J0108 carries no Type/SIL/PL rating anywhere in its specification. Its digital inputs trip at an ordinary ~3V threshold and are only rated for normal DC 0-30V terminal stress and <250V basic isolation (type-tested to DC 1000V/60s) - nothing qualifies any input as an OSSD or a safety-rated channel, and the module has no dual-channel safety logic or forced-guided contact monitoring.
Use instead: DA31 Emergency-Stop Safety Relay Module (Cat.4/PL e/SIL 3) or DQSRN Safety Relay Module (DIP-switch selectable E-stop/OSSD/door-interlock/two-hand, Cat.4/PL e/SIL 3).
The host system communicates over Ethernet/EtherCAT, PROFIBUS, CANopen, or another fieldbus rather than serial Modbus.
Why not: D3J0108's only communication paths are RS-485 running Modbus-RTU (default 9600bps, 8 data bits, even parity, 1 stop bit), plus Modbus-ASCII, AT commands, a USB port, and an optional 2.4GHz wireless Modbus-OTA link - no other fieldbus stack is listed in its specification.
Use instead: No module in the D3J01/D3J02/D3J03/D4G0206 lineup speaks anything but Modbus-RTU/ASCII; pair the module with a separate Modbus-to-fieldbus gateway if the host requires a different protocol.
The signals need to drive a local action by themselves, without a PLC or SCADA host doing the polling and decision-making.
Why not: D3J0108 only exposes its input states to whatever master polls it over Modbus-RTU (or, if enabled, pushes them via interval/change-triggered auto-reporting) - it has no ladder logic, no local decision engine, and no output of any kind to act on a decision.
Use instead: D4G0206 Relay Module, a graphical schematic-programmed micro-PLC with 6 inputs and 4 relay/transistor outputs that runs its own logic without a host.
Specifications we do not publish yet
We only publish a figure once we are confident it is true. The items below are still being validated through further testing and real-world customer feedback, so for now we would rather leave them open than guess. If one of them matters to your design, ask us for the latest validated status.
- Ingress protection (IP) rating for the D3J0108 enclosure is not stated in the source specification.
- MTBF or expected service life for D3J0108 is not stated in the source specification.
- Terminal wire gauge (AWG/mm²) accepted by D3J0108's 5.08mm-pitch screw terminals is not stated in the source specification.
- Per-channel input current draw for D3J0108 is not stated - only total supply current (<1500mA) is given in the source specification.
- Maximum number of RS-485 nodes per bus segment and maximum cable length for D3J0108 are not stated in the source specification.
- A radiated/conducted EMC emission standard for D3J0108 is not stated - the source specification only lists ESD/EFT/surge immunity test levels.
- Module weight for D3J0108 is not stated - only the 72 x 88 x 59mm dimensions are given in the source specification.
Frequently Asked Questions
What is the D3J0108 used for?
Can the D3J0108 be configured or operated over USB instead of RS-485?
How many input channels does the D3J0108 have, and are there extras?
What are the default communication settings?
How does input edge counting and filtering work?
Can I add a wireless connection instead of wiring RS-485?
Does the D3J0108 have any certifications?
Works Well Together
On the same machine or line, D3J0108 is typically ordered together with: Proximity Sensors · Photoelectric Sensors · Laser Distance Sensors
D6.5 Series Inductive Proximity Sensors (Ultra-Short 18mm / Y-Type / 35mm / 45mm)
6.5mm-diameter inductive proximity sensors for tight-clearance mounting where M8 sensors won't fit.
BGS-CX441 / BGS-CX442 Background Suppression Photoelectric Sensor
Wire-adjustable BGS sensor with 2 mm or 15 mm spot, 10-300 mm range, published black/white differential distance.
DDA-Y & DDB-Y Industrial Laser Distance Sensor (Phase-Shift)
Phase-shift laser distance sensors: 0.2-100 m range, millimeter accuracy, RS485 Modbus RTU, switching or analog output.
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