Description
QEED Modbus I/O System
QA-12DI-4DO Digital I/O Interface
The QEED QA-12DI-4DO is a Modbus RTU slave digital I/O expansion module with 12 digital inputs and 4 SPDT relay outputs. It is designed for master systems such as PLC, HMI, Panel PC, SCADA, BMS, EMS and industrial IoT platforms where additional input and output points are required.
The module supports RS485 Modbus RTU communication, DIN rail mounting, optional T-BUS connection, Q-WIZARD configuration and hot swapping. It is suitable for digital status monitoring, pulse counting, alarm signalling and relay-based control applications.
Digital Inputs
12 x PNP inputs with counter / totalizer function
Relay Outputs
4 x SPDT relay outputs, 5A / 250Vac
Communication
RS485 Modbus RTU slave
Mounting
DIN rail, with optional T-BUS connection
Overview
QA-12DI-4DO is used when a Modbus master system needs to collect multiple field input statuses and control several relay outputs from a compact DIN rail module. It combines digital input monitoring, pulse counting and relay output control in one RS485 Modbus RTU device.
The module is suitable for automation panels, machine monitoring, energy management panels, utility monitoring systems, building management systems and industrial IoT installations where switches, counters, alarm contacts and output relays must be connected to a central platform.
Positioning: Compact 12DI + 4DO Modbus RTU I/O expansion module for PLC, HMI, SCADA, BMS, EMS, IoT gateways and IoTWatt 4.0 applications.
Key Features
12 Digital Inputs
PNP digital inputs with common negative, suitable for status monitoring and pulse counting.
Counter / Totalizer Inputs
Each input can be used for 32-bit counter / totalizer applications with pulsed inputs up to 10kHz.
4 Relay Outputs
4 SPDT relay outputs rated 5A / 250Vac for alarm, control and remote switching functions.
RS485 Modbus RTU
Communicates as a Modbus RTU slave through RS485 terminals or optional T-BUS connection.
Q-WIZARD Configuration
Configuration can be done using Q-WIZARD software through micro USB or RS485.
Hot Swapping
Module can be inserted or removed without needing to restart the connected Modbus master system.
Digital Inputs and Outputs
| Function |
Specification |
Typical Use |
| Digital Inputs |
12 x PNP inputs with common negative |
Status monitoring, alarm input, switch feedback, machine status |
| Counter Inputs |
12 x 32-bit counter / totalizer inputs, pulsed input up to 10kHz |
Pulse meters, production counters, equipment event counting |
| Digital Output Supply |
12Vdc output for detecting optomos contact presence |
Input excitation / contact detection support |
| Relay Outputs |
4 x SPDT relay outputs, 5A / 250Vac |
Alarm output, remote control, interlock, equipment enable / disable |
| Serial Output |
RS485 Modbus RTU slave |
PLC, HMI, SCADA, EMS, BMS, gateway and IoT system integration |
Typical Applications
PLC I/O Expansion
Add additional digital inputs and relay outputs to PLC systems through Modbus RTU.
Building Management
Collect alarm contacts, switch feedback and control outputs for BMS applications.
Energy Management
Collect pulse counts, equipment run status and control outputs for EMS and IoTWatt 4.0.
Machine Monitoring
Monitor machine status, production counters, trips and alarm contacts in automation panels.
Utility Monitoring
Use inputs for water, gas, compressed air or energy meter pulse collection.
Remote Relay Control
Use relay outputs for alarm annunciation, permissive signals or simple remote switching.
Technical Specifications
| Parameter |
Specification |
| Power Supply |
10 to 40 Vdc or 20 to 28 Vac, 50/60 Hz |
| Inputs |
12 PNP digital inputs, common negative, counter / totalizer inputs |
| Input Frequency |
Pulsed inputs up to 10kHz |
| Outputs |
4 SPDT relay outputs, 5A / 250Vac |
| Serial Communication |
RS485 Modbus RTU slave |
| Protection Degree |
IP20 |
| Working Temperature |
-15°C to +60°C |
| Storage Temperature |
-40°C to +85°C |
| Relative Humidity |
10% to 90%, non-condensing |
| Elevation |
Up to 2000m a.s.l. |
| Dimensions |
115 x 111 x 18 mm |
| Weight |
140g |
| Terminal Cable Cross-Section |
0.05 to 1.5 mm², 30 to 14 AWG |
RS485 Modbus and T-BUS Connection
QA-12DI-4DO communicates through RS485 Modbus RTU using the A+, B- and GND terminals. It can also be mounted with the optional T-BUS accessory, which allows both power supply and serial communication to be carried through the module base for reduced panel wiring.
- RS485 Modbus RTU slave communication
- Terminals for GND, B- and A+ RS485 connection
- Optional T-BUS accessory for power and RS485 bus connection
- DIP-switch setting for Modbus address and baud rate
- Dynamic 120Ω RS485 bus termination through DIP switch when used as last module
RS485 note: For stable RS485 networks, use proper cable, address setting, baud rate setting and 120Ω termination at the beginning and end of the RS485 bus where required.
Configuration Functions
The module can be configured using Q-WIZARD software through the micro USB port or through RS485 Modbus RTU. It can also be configured by a third-party Modbus RTU master using the relevant registers.
- Modbus address, baud rate, parity and stop bit adjustment
- Counting on rising or falling edge
- Incrementing or decrementing counter setting
- Input filtering levels to reduce contact bounce effects
- Digital output status control by operator / Modbus register
- Memory retention of output states and totalizers after reboot
- Real-time monitoring of device variables through Q-WIZARD
Status Indication
| LED / Indicator |
Function |
| Fail |
Yellow LED indicates one or more module anomalies or errors |
| RX |
Red LED flashes when the system is receiving data on RS485 |
| TX |
Red LED flashes when the system is transmitting data on RS485 |
| O1 to O4 |
Green LEDs indicate active digital outputs |
| I1 to I12 |
Green LEDs indicate active digital inputs |
System Integration
QA-12DI-4DO is suitable for connecting field digital signals and relay outputs into industrial automation and monitoring systems. It can be used with PLC, HMI, SCADA, BMS, EMS, Modbus gateway, IoT gateway and IoTWatt 4.0 installations.
- Digital status monitoring for equipment, panels and alarms
- Pulse counting for meters, counters and production signals
- Relay outputs for control, alarm and remote switching
- RS485 Modbus RTU connection to supervisory systems
- Integration into IoTWatt 4.0 through RS485 Modbus gateways
Design note: Relay outputs should be selected and wired according to the load type, voltage, current rating, isolation requirement and control philosophy.
QEED QA-12DI-4DO Supply and Integration
Saturn Pyro supports QEED QA-12DI-4DO Modbus I/O modules for industrial automation, building management, energy management, utility monitoring, SCADA, BMS, EMS, IoT gateway and IoTWatt 4.0 integration projects in Malaysia.
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